The figure is the least for the same period over the last six years, according to the Municipal Bureau of Environmental Protection.

This has made it more difficult for the Chinese capital to reach its goal of having 238"blue sky" days this year, eight more than that in 2005.

Experts said the capital is faced with quite a number of difficulties to achieve the goal because of the ever increasing autos, energy consumption and construction sites.

The number of motor vehicles in Beijing is growing by 10 percent year-on-year, and coal remains the major source of energy.

Each year, the city sees more than 100 million square meters of construction sites to start or re-start.

Beijing launched the campaign of "Defending the Blue Sky" in 1998, which saw only 100 days of blue sky.

It has removed 4,000 old polluting buses and 30,000 cabs from service this year and replaced them with vehicles meeting newly promulgated, more rigid state standards for pollution control. Enditem