Beijingers had only 15 "blue sky" days in February, the least in the same period in past three years, according to the monthly report of the municipal environment watchdog.

Beijing witnessed frequent foggy and hazy weather in February, which is hard for pollutants to diffuse. Dust and smog caused by fireworks during the Spring Festival also served as a major source of pollutants.

The Chinese capital's ambitious target of 245 "blue sky" days this year got off to a bad start. Statistics show in the first two months, Beijing records only 35 "blue sky" days.

The city reached its annual target of 238 "blue sky" days for 2006 by December 24, and then added three more to the total before New Year's Day.