The average concentration of PM 2.5 - fine particulate matter that is hazardous to human health - in Beijing dropped to 23 micrograms per cubic meter in August, a record low in history since monitoring, the Beijing Municipal Ecological Environment Bureau said on Thursday.

In fact, it was the first time Beijing's PM 2.5 level went below 30 micrograms per cubic meter, data from the bureau showed.

In addition, the average concentration of PM 2.5 in the first eight months was 42 micrograms per cu m, which was also a record low.

During the first eight months, Beijing saw 150 days with good air quality. Only three days were reported to have severe air pollution, five less compared with the same period last year.

Meanwhile the government warned of the increasing possibilities and challenges of worsening air quality in the coming autumn and winter due to disadvantageous weather to disperse the pollutants and increasing emission levels.