Air pollution has been one of the hottest topics in Shanghai's two sessions this year, as residents living in the Yangtze River Delta breathed the most polluted air in five years during the past two weeks.

The delta is working on a collaborative treatment plan on air pollution to reduce carbon emissions by 6 percent by 2015 in the region, according to Zhang Quan, director of Shanghai Environmental Protection Bureau. Zhang attended the Shanghai Municipal People's Congress, the city's top legislature's annual meeting that opened on Sunday.

Zhang said the plan will be released in the third quarter.