A girl salutes as others take pictures of themselves during a flag-raising ceremony at the Tiananmen Square in Beijing, China June 4, 2016. REUTERS/Damir Sagolj 

Visitors look at Mausoleum of late Chinese chairman Mao Zedong at Tiananmen Square on the 50th anniversary of the start of the Cultural Revolution in Beijing, China, May 16, 2016. REUTERS/Kim Kyung-Hoon 

A cleaner sweeps ground in front of the Mausoleum of late Chinese chairman Mao Zedong at Tiananmen Square on the 50th anniversary of the start of the Cultural Revolution in Beijing, China, May 16, 2016. REUTERS/Kim Kyung-Hoon 

Paramilitary solders stand guard at Tiananmen Square where the portrait of late Chinese chairman Mao Zedong is seen, on the 50th anniversary of the start of the Cultural Revolution in Beijing, China, May 16, 2016. REUTERS/Kim Kyung-Hoon 

A soldier (L) stands guard outside the Great Hall of the People, the venue of the ongoing National People's Congress (NPC), China's parliament, in Beijing, China, March 7, 2016. REUTERS/Jason Lee 

A soldier stands guard outside the Great Hall of the People, the venue of the ongoing National People's Congress (NPC), China's parliament, in Beijing, China, March 7, 2016. REUTERS/Jason Lee 

A soldier stands guard outside the Great Hall of the People, the venue of the ongoing National People's Congress (NPC), China's parliament, in Beijing, China, March 7, 2016. REUTERS/Jason Lee 

A soldier facing to Tiananmen Gate stands guard outside the Great Hall of the People, the venue of the ongoing National People's Congress (NPC), China's parliament, in Beijing, China, March 7, 2016. REUTERS/Jason Lee 

Hostesses jump for pictures at the Tiananmen Square during the opening session of the Chinese People's Political Consultative Conference (CPPCC) at the near-by Great Hall of the People in Beijing, China, March 3, 2016. REUTERS/Damir Sagolj 

Hostesses pose for pictures at the Tiananmen Square during the opening session of the Chinese People's Political Consultative Conference (CPPCC) at the near-by Great Hall of the People in Beijing, China, March 3, 2016. REUTERS/Damir Sagolj 

Hostesses and a man pose for pictures at the Tiananmen Square during the opening session of the Chinese People's Political Consultative Conference (CPPCC) at the near-by Great Hall of the People in Beijing, China, March 3, 2016. REUTERS/Damir Sagolj 

A man sells souvenirs bearing the images of China's President Xi Jinping (R) and Chinese late Chairman Mao Zedong at Tiananmen Square as the area near the Great Hall of the People is prepared for upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing March 3, 2016. REUTERS/Damir Sagolj 

People leave Tiananmen Square shortly after a flag-raising ceremony as the area near the Great Hall of the People is prepared for upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing March 3, 2016. REUTERS/Damir Sagolj 

People attend a flag-raising ceremony at Tiananmen Square as the area near the Great Hall of the People is prepared for upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing March 3, 2016. REUTERS/Damir Sagolj 

A paramilitary policeman tells women wearing traditional clothes to leave Tiananmen Square shortly after a flag-raising ceremony as the area near the Great Hall of the People is prepared for upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing March 3, 2016. REUTERS/Damir Sagolj 

People use selfie sticks and lift up their mobile phones and cameras to record and take pictures of a flag-raising ceremony at Tiananmen Square as the area near the Great Hall of the People is prepared for upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing March 3, 2016. REUTERS/Damir Sagolj TPX IMAGES OF THE DAY

Paramilitary policemen tell people to leave Tiananmen Square shortly after a flag-raising ceremony as the area near the Great Hall of the People is prepared for upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing March 3, 2016. REUTERS/Damir Sagolj 

Paramilitary policemen arrive at Tiananmen Square as the area near the Great Hall of the People is prepared for upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing, China March 3, 2016. REUTERS/Damir Sagolj 

Paramilitary policemen march at Tiananmen Square as the area near the Great Hall of the People is prepared for upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing, China March 3, 2016. REUTERS/Damir Sagolj 

A paramilitary policeman tells people to leave Tiananmen Square shortly after a flag-raising ceremony as the area near the Great Hall of the People is prepared for upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing March 3, 2016. REUTERS/Damir Sagolj 

Women wearing traditional clothes take pictures of themselves after a flag-raising ceremony at Tiananmen Square as the area near the Great Hall of the People prepares for upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing March 3, 2016. REUTERS/Damir Sagolj 

Paramilitary policemen march at Tiananmen square as the area near the Great Hall of the People is prepared for the upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing, China March 3, 2016. REUTERS/Damir Sagolj 

Security personnel carry items at Tiananmen square as the area near the Great Hall of the People is prepared for upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing, China March 3, 2016. REUTERS/Damir Sagolj 

Women wearing traditional clothes attend a flag-raising ceremony at Tiananmen Square as the area near the Great Hall of the People is prepared for the upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing March 3, 2016. REUTERS/Damir Sagolj 

A paramilitary policeman tells people to leave Tiananmen Square shortly after a flag-raising ceremony as the area near the Great Hall of the People is prepared for the upcoming annual sessions of the National People's Congress (NPC) and Chinese People's Political Consultative Conference (CPPCC) in Beijing March 3, 2016. REUTERS/Damir Sagolj 

A man smiles as his picture is taken just after a flag-raising ceremony amid heavy smog at the Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

People gather at the Tiananmen Square for a flag-raising ceremony amid heavy smog, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

People prepare their cameras and national flags before a flag-raising ceremony amid heavy smog at the Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

People gather before sunrise at Tiananmen Square for a flag-raising ceremony amid heavy smog, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

A man films as people gather for a flag-raising ceremony amid heavy smog at Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

People with national flags have their picture taken just after a flag-raising ceremony amid heavy smog at Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

People have their cameras ready before a flag-raising ceremony amid heavy smog at Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

Paramilitary policemen wearing masks march on a cold morning following a flag-raising ceremony amid heavy smog at Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

People gather before sunrise at Tiananmen Square for a flag-raising ceremony amid heavy smog, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

People gather before sunrise at Tiananmen Square for a flag-raising ceremony amid heavy smog, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

Paramilitary policemen wear masks on a cold morning as people gather for a flag-raising ceremony amid heavy smog at the Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

A woman wearing a protective mask has her picture taken just after a flag-raising ceremony amid heavy smog at the Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

A paramilitary policeman wears a mask on a cold morning as people gather for a flag-raising ceremony amid heavy smog at the Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

People film with their cameras during a flag-raising ceremony amid heavy smog at the Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj TPX IMAGES OF THE DAY

People have their cameras ready before a flag-raising ceremony amid heavy smog at the Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

People gather before the sunrise at the Tiananmen Square for a flag-raising ceremony amid heavy smog, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

A man has his picture taken just after a flag-raising ceremony amid heavy smog at the Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

People gather before dawn at the Tiananmen Square for a flag-raising ceremony amid heavy smog, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

People film with their cameras during a flag-raising ceremony amid heavy smog at the Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj TPX IMAGES OF THE DAY

A paramilitary policeman wears a mask on a cold morning as people gather for a flag-raising ceremony amid heavy smog at the Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj 

People have their cameras ready before a flag-raising ceremony amid heavy smog at the Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj TPX IMAGES OF THE DAY

People have their pictures taken at the Monument to the People's Heroes at the Tiananmen Square in Beijing December 8, 2015 as China's capital issues its first ever "red alert" for pollution. REUTERS/Damir Sagolj 

People wearing masks protecting from extreme smog visit the Tiananmen Square in Beijing December 8, 2015 as China's capital issues its first ever "red alert" for pollution. REUTERS/Damir Sagolj 

Policemen wear masks protecting from extreme smog at the Tiananmen Square in Beijing December 8, 2015 as China's capital issues its first ever "red alert" for pollution. REUTERS/Damir Sagolj 

Women wearing masks protecting them from extreme smog take pictures of themselves at the Tiananmen Gate in Beijing December 8, 2015 as China's capital issues its first ever "red alert" for pollution. REUTERS/Damir Sagolj 

Visitors stand next to a paramilitary policeman as they visit the Tiananmen Square on a sunny day December 2, 2015, after a fresh cold front cleared the smog that was blanketing Beijing, China. REUTERS/Damir Sagolj 

A giant portrait of Chinese late chairman Mao Zedong is seen on the Tiananmen gate on a sunny day December 2, 2015, after a fresh cold front cleared the smog that was blanketing Beijing, China. REUTERS/Damir Sagolj 

Visitors stand next to a paramilitary policeman (C) as they visit the Tiananmen Square on a sunny day December 2, 2015, after a fresh cold front cleared the smog that was blanketing Beijing, China. REUTERS/Damir Sagolj 

Visitors pose for photographs in front of the Tiananmen Gate and the giant portrait of Chinese late Chairman Mao Zedong on a sunny day December 2, 2015, after a fresh cold front cleared the smog that was blanketing Beijing, China. REUTERS/Damir Sagolj 

A combination photo shows visitors standing next to a paramilitary policeman as they visit the Tiananmen Square on a smoggy day on December 1, 2015 (top), and on a sunny day on December 2, 2015 (bottom), after a fresh cold front cleared the smog that was blanketing Beijing, China. REUTERS/Damir Sagolj 

A combination photo shows visitors standing next to a paramilitary policeman as they visit the Tiananmen Square on a smoggy day on December 1, 2015 (top), and on a sunny day on December 2, 2015 (bottom), after a fresh cold front cleared the smog that was blanketing Beijing, China. REUTERS/Damir Sagolj 

A combination photo shows visitors posing for photographs in front of the Tiananmen Gate and the giant portrait of Chinese late Chairman Mao Zedong on a smoggy day on December 1, 2015 (top), and on a sunny day on December 2, 2015 (bottom), after a fresh cold front cleared the smog that was blanketing Beijing, China. REUTERS/Damir Sagolj 

A paramilitary policeman stands guard behind people waiting to enter the Tiananmen Square on a sunny day with no pollution after a period of hazardous, choking smog that was blanketing Beijing, China December 2, 2015. REUTERS/Damir Sagolj 

A couple wearing protective masks visit the Tiananmen Gate on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. REUTERS/Damir Sagolj 

Policemen wear protective masks at the Tiananmen Square on an extremely polluted day as hazardous, choking smog continues to blanket Beijing, China December 1, 2015. REUTERS/Damir Sagolj