(Beijing) – The Ministry of Environmental Protection is preparing a system that would provide the public with air pollution forecasts, a senior official said on April 1.

The ministry told major cities around the country to have the system to provide forecasts of smog levels for the coming few hours to a few days ready by October 31, environmental vice minister Wu Xiaoqing said at a conference.

The cities that will provide the forecasts, which will appear on the ministry's website, are provincial capitals, other big cities in the east and China's four municipalities, namely Beijing, Tianjin, Shanghai and Chongqing.

Wu did not say when the forecasts will be available to the public.

An air quality monitoring network that the government started building in 2012 will provide data for the forecasts. The environmental ministry said at the end of last year that the monitoring network is in place.

That data gathering system comprises 552 monitoring sites in 117 cities.

China's northern and eastern regions have battled heavy smog in recent years. The region known as "Jing Jin Ji" – Beijing, Tianjin and Hebei – has suffered with especially bad air.

The country's fight against air pollution has gained more urgency as Beijing and Zhangjiakou, in neighboring Hebei, compete with Kazakhstan's Almaty to host the Winter Olympics in 2022. Air quality and traffic are the two main concerns with the Chinese cities' suitability as co-hosts.

The ministry has also set a deadline of November 30 for regulators to compile a list of major pollutants in 13 cities, including Beijing, Tianjin and Shanghai. Another 26 cities need to do the same by the end of the year.

Wu said that vehicle emissions are the top pollutant in Beijing, Hangzhou, Guangzhou and Shenzhen, and that emissions from coal burning were the main problem in Shijiazhuang and Nanjing.

Dust, emissions from manufacturers and pollutants drifting in from other areas were contributing to smog in Tianjin, Shanghai and Ningbo, he said.

Official data show that vehicle emissions contribute 31.1 percent of PM 2.5 in Beijing's air. Coal burning, factory emissions and dust accounted for 22.4 percent, 18.1 percent and 14.3 percent, respectively. PM 2.5 refers to fine particles in the air that are 2.5 micrometers in diameter that can harm human health and reduce visibility.

(Rewritten by Li Rongde)