A pigeon flies out of a pedestrian subway at Charing Cross station after it was shut due to a gas leak, in London, Britain, January 23, 2018. REUTERS/Dylan Martinez TPX IMAGES OF THE DAY

Police tape blocks the Strand near Charing Cross station after it was shut due to a gas leak, in London, Britain, January 23, 2018. REUTERS/Dylan Martinez

Police officers walk towards Charing Cross station after it was shut due to a gas leak, in London, Britain, January 23, 2018. REUTERS/Dylan Martinez

Police tape blocks the Strand near Charing Cross station after it was shut due to a gas leak, in London, Britain, January 23, 2018. REUTERS/Dylan Martinez

A pigeon flies out of a pedestrian subway at Charing Cross station after it was shut due to a gas leak, in London, Britain, January 23, 2018. REUTERS/Dylan Martinez

Porter Ranch resident Judy Kim holds a protest sign outside Los Angeles City Hall during a demonstration ahead of the testimony before the Los Angeles City Council on the ongoing natural gas leak in the Porter Ranch area of Los Angeles, California, December 1, 2015. REUTERS/Gus Ruelas

Porter Ranch residents Danielle Michaels (L) and Michelle Theriault hold signs outside Los Angeles City Hall during a demonstration ahead of the testimony before the Los Angeles City Council on the ongoing natural gas leak in the Porter Ranch area of Los Angeles, California, December 1, 2015. REUTERS/Gus Ruelas

Porter Ranch residents Danielle Michaels (L) and Michelle Theriault (R) hold signs outside Los Angeles City Hall during a demonstration ahead of the testimony before the Los Angeles City Council on the ongoing natural gas leak in the Porter Ranch area of Los Angeles, California December 1, 2015. REUTERS/Gus Ruelas

TOTAL-GASLEAK/ELGIN - 3D diagram of Total's abandoned Elgin platform in the North Sea. RNGS. (SIN02)

TOTAL-GASLEAK/ELGIN - 3D diagram of Total's abandoned Elgin platform in the North Sea. RNGS. (SIN02)

TOTAL-GASLEAK/ - Map locating a major gas leak at Total abandoned Elgin platform in the North Sea. RNGS. (SIN02)

TOTAL-GASLEAK/ - Map locating a major gas leak at Total abandoned Elgin platform in the North Sea. RNGS. (SIN02)

Office workers and pedestrians walk south to north over the Sydney Harbour Bridge with the city skyline in the background February 5, 2004. Sydney's central business district underground rail network was shut down and thousands of workers and commuters evacuated from stations due to a suspected major gas leak. REUTERS/Will Burgess DG/PB

Members of the public sit outside Sydney's Wynyard train station after it was closed due to a suspected gas leak February 5, 2004. Sydney's central business district underground rail network was shut down and thousands of lunchtime office workers and commuters evacuated from stations due to a suspected major gas leak. REUTERS/David Gray DG/PB

A security guard talks to firemen as they go to check a suspected gas leak at Sydney's Wynyard train station February 5, 2004. Sydney's central business district underground rail network was shut down and thousands of lunchtime office workers and commuters evacuated from stations due to a suspected major gas leak. REUTERS/David Gray DG/PB

A security guard (L) tells a member of the public to leave due to a suspected gas leak at Sydney's Wynyard train station February 5, 2004. Sydney's central business district underground rail network was shut down and thousands of lunchtime office workers and commuters were evacuated from stations due to a suspected major gas leak. REUTERS/David Gray DG/PB

Masked protesters take part in a silent demonstration, while holding a
poster showing Union Carbide chairman Warren Anderson outside a court
in protest at reducing charges against Anderson in the central Indian
city of Bhopal August 27, 2002. An Indian court will consider on
Tuesday a federal police petition seeking to reduce charges against the
former chairman of U.S.-based Union Carbide over a gas leak disaster
that killed 3,000 people in December 1984. REUTERS/Raj Patidar

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