ULAN BATOR, April 17 (Xinhua) -- The Mongolian capital's housing prices in the first quarter this year increased by 82.1 percent compared to the fourth quarter of 2010, official data from the country's National Statistics Office showed Tuesday.

However, the housing prices in the city dropped by 0.5 percent in the first quarter of this year compared to the end of last year.

Currently, more than 800,000 residents, over half of Ulan Bator's population, who can't afford an apartment, live in slums, also known as ger districts.

They have to rely on burning raw coal and other flammable materials such as plastics and old tires to stay warm and cook meals during the six-month-long winter season.

It is estimated that 80 percent of air pollution in the city is caused by ger stoves. The rising housing prices thus are a factor contributing to the air pollution in the capital.

The city's air pollution on Jan. 30 exceeded 133 times the safety level set by the World Health Organization.