BEIJING — China’s environment ministry on Nov 6 advised local authorities to lift their orange alert for air pollution as air quality had improved thanks to emergency measures.

The Ministry of Environmental Protection (MEP) previously forecast that the Beijing-Tianjin-Hebei region and nearby areas would see severe air pollution from Nov 4 to 8, prompting local governments to issue the orange alert, the second highest level, last week.

But as authorities adopted a raft of emergency measures to meet the smog challenge, most of the areas experienced slight air pollution or even good air on Nov 6.

The MEP said authorities should decide the timing on lifting the orange alert based on local air conditions and weather forecasts.

The orange alert brings several measures, including restricting the use of vehicles, increasing pollution controls at construction sites, and temporarily restricting or stopping production activities of steel, cement and coal firms.

The emergency efforts reduced around 20 percent of pollutants, effectively curbing the increasing PM 2.5 density and making the air quality better than forecast, according to Chai Fahe, an expert with the Chinese Research Academy of Environmental Sciences.

Air quality usually worsens in late autumn and winter in northern China due to increased emissions from heating sources and less wind.