A tricycle travels past a crossroad on a hazy day in Hefei, Anhui province March 30, 2014. China's plan for a market in air pollution permits promises to help clean up its air cheaply, but the move could prove just as useless as previous environmental policies unless the government stamps out lax enforcement and spotty data. REUTERS/Stringer (CHINA - Tags: ENVIRONMENT TRANSPORT TPX IMAGES OF THE DAY)