The Shanghai government is studying the possibility of building a reservoir upstream of the Huangpu River to improve tap water while also working on an action plan to improve air quality.

Construction of Dongfengxisha Reservoir, which will mainly provide tap water to residents on Chongming Island, will be completed by January, said Zhang Quan, director of the Shanghai Environmental Protection Bureau, yesterday, the World Environment Day.

Zhang said the government is discussing building another reservoir because sourcing tap water from open sources isn't as safe since ships cause pollution from diesel discharges and dumping garbage. Shipping accidents can also cause leaks of toxic chemicals and fuel, Zhang added.

The director said the city has stopped sourcing water from many small and mid-sized waterways and will continue phasing this out.

Air quality is another major concern of residents and "air pollution treatment is our key task this year," Zhang said.

Routine pollutants in the air are dropping while PM2.5 particles are now a major pollutant, according to a Shanghai Environmental Bulletin released yesterday.

The bulletin said 59 days in the first three months of this year were not polluted. The figure is based on stricter criteria as the city is now measuring levels of PM2.5 particles, including ozone and carbon monoxide.

The average density of PM2.5 from June 27 to December 31 was 48 micrograms per cubic meter, higher than the national limit of 35 micrograms per cubic meter.

"We are working on an action plan in order to drop PM2.5 density and reduce pollution as quickly as possible," Zhang said. "Using cleaner sources of energy, reducing energy consumption, eliminating cars that emit lots of pollutants and limiting waste discharges by factories are all useful measures.

"A draft law has been completed, but improvements and other details still need to be finalized."