Beijing has issued two red alerts against air pollution in two weeks. This signifies heavier pollution, but it also shows that the authorities have become more vigilant to air pollution. Seen together with the other measures it has taken, we can say the Beijing municipal government has been more determined in 2015 to curb air pollution.

Opinions on the root causes of air pollution in China differ, but there are some common factors. Burning of coal is the first. China still burns coal to generate about 70 percent of its electricity and its annual coal consumption is more than 4 billion tons.

Earlier this month, the Chinese government announced on its official website a plan to improve technologies and reduce the ratio of coal in power generation to less than 310 grams per kilowatt hour. The plan will hopefully save 100 million tons of coal a year by 2020 and, along with other measures to reduce the reliance on coal, greatly improve the air quality.

The second problem is the poor quality of petroleum we use because China does not get the supply of good quality oil and its processing plants are not that efficient. The petroleum used in China has quite a high percentage of aromatic hydrocarbons.

Way back in the 1990s, the then ministry of chemical industries had said it feared that the use of such oil would release more particulates into the air. That fear has come true, as can be seen from the smog over large parts of North China for the past few years.

The key to solving this problem lies in introducing new-energy automobiles and encouraging people to use electric or hybrid cars. The government is already promoting such vehicles, for which it had set up more than 40,000 charging posts in some major cities by September - and has vowed to build more.

Besides, municipal governments should try to replace buses running on fossil fuels with those that operate on natural gas, because natural gas emits less greenhouse gases and particulates, and is abundant in China.