Yunnan provincial officials said on Tuesday that new facilities will be installed to tackle wastewater and exhaust gas at a controversial oil refinery in Kunming, the provincial capital, and promised to keep a close eye on the air quality there.

The China National Petroleum Corp refinery in the city of Anning, which will manufacture 10 million metric tons of oil a year, sparked controversy in local communities due to its potentially negative environmental impact.

The refinery will emit 2,500 tons of poisonous sulfur dioxide and 1,270 tons of nitrogen oxides each year, said Zhou Dongfeng, senior engineer at Yunnan Institute of Environmental Sciences. He also said the factory will discharge 147 cubic meters of wastewater per hour, or 1.29 million tons a year.