The Chinese capital Beijing issued its second red alert for smog in a month Friday, just days after the city issued its first ever such warning. The warning led to restrictions on vehicles as well as strict rules for factories and buildings, while schools in the region closed down.

Beijing’s government website reportedly said Friday that smog of 22.5 million is set to settle over the city from Saturday to Tuesday. The government also said, according to the Associated Press (AP), that airborne particle level of PM2.5, which are the smallest and the deadliest, will rise to as high as 500 in the city. The expected level is set to reach 20 times more than the level that is considered safe by the World Health Organization, which recommends a maximum 25 micrograms per cubic meters.

Outdoor activities like fireworks and barbecue grills will not be allowed while half the cars in the city will be taken off the roads adhering to the odd-even license plate system, Xinhua reported. Residents have been advised to stay indoors.

The city government expects that on Tuesday the visibility in some parts will be reduced to less than 500 meters (1,600 feet) and authorities said that the pollution levels in the city will be worse than the last time the government issued the smog red alert last Monday. The area from Xian in central China to Harbin in the northeastern part of the country is expected to be affected due to high pollution, the National Meteorological Centre said, according to BBC.

The report by AP said that smog red alerts are issued when levels of PM2.5 are set to last for more than 72 hours. The four-tier smog alerts were introduced two years ago, but have never been issued before this month. The city, however, has been accused of not issuing smog warnings earlier, despite heavy particles in the air, to avoid the costs.

Studies say that every year about 1.4 million premature deaths annually in China, or about 4,000 a day, occur due to heavy pollution levels, the AP reported.

The latest red alert comes on the heels of a historic climate deal in Paris Saturday, when 195 countries agreed to keep the global warming increase below 2 degrees Celsius by 2050.