40 Chinese cities reel under heavy pollution for third day

As many as 35 flights were delayed or cancelled; highways into the city of 7.5 million people were closed due to 'extremely low visibility'

Heavy smog continued to engulf 40 Chinese cities for the third day today, with many of them under red alert for severe air pollution, as China's environmental watchdog said the situation is likely to worsen further due to unfavourable weather conditions.

While 23 cities in north China, including Beijing and Tianjin, have activated red alerts as the air began to turn hazy starting Friday, 17 other cities declared orange alerts, the second highest alert invoking emergency measures, state- run CCTV said.

As many as 35 flights in Tianjin, east of here, were delayed or cancelled and highways into the city of 7.5 million people were closed due to "extremely low visibility", according to state-run Xinhua news agency.

Beijing and other local governments have imposed odd-even car restrictions on roads and cut emissions for factories.

The heavy smog came a bit later than previously forecast as efforts paid off, and pollutant density in the air has somewhat been reduced in these cities, Chinese Ministry of Environmental Protection said.

However, further observation is needed to confirm the actual effects of these measures, and air pollution is still likely to worsen as weather conditions continue to be unfavourable, the ministry said in a statement.

Pollution levels are likely to peak between today and tomorrow, it said, adding there will be another peak on Wednesday, Xinhua reported citing the statement.

The ministry has sent 13 inspection teams to check whether local governments have taken appropriate measures to address heavy pollution and sanction illegal factory emissions.

In Beijing, the air quality index (AQI) reading reached 253 indicating heavily polluted air, according to the Beijing Municipal Environmental Monitoring Centre.

China's National Meteorological Centre (NMC) maintained an orange alert for smog today for north China, warning that air pollution will be the most severe from tomorrow evening to Wednesday.

Some regions will see PM2.5 density levels exceeding 500, the NMC said, adding the smog is expected to disperse from Wednesday night.

China has a four-tier warning system for severe weather, with red being the most serious, followed by orange, yellow and blue.