China's heavily polluted capital, Beijing, plans to reduce air pollution levels by 15 percent by 2015 and 30 percent by 2020 through phasing out old cars, relocating factories and planting new forests, state media said on Thursday.

The level of air pollution in the capital varies, depending on winds. But a cocktail of smokestack emissions, vehicle exhaust, dust and aerosols have at times blanketed Beijing in a pungent, beige shroud for days on end over the past few months, and has even forced the cancellation of flights.

The overall environmental performance is improving in Sri Lanka and it has been ranked as a moderate performer, according to the 2012 Environmental Performance Index (EPI) released during the World Economic Forum in Davos, Switzerland last week.

India has the worst air quality in the world, beating even its neighbour China, according to an annual survey based at Yale and Columbia universities in the United States.

Of all the countries surveyed in the Environmental Performance Index (EPI), which measures the effects of polluted air on human health, India ranked the lowest at 132.

The study used satellite data to measure air pollution concentrations.

Sri Lanka's overall environmental performance is improving and the country has been ranked as a modest performer according to a study on global environment released during this year's World Economic Forum in Davos, Switzerland last week.

Sri Lanka has been ranked at the 55th place, six places below the United States ranked at 49th, in the 2012 Environmental Performance Index (EPI) prepared by the Yale University in the United States.

India has the worst air pollution in the entire world, beating China, Pakistan, Nepal and Bangladesh, according to a study released during this year’s World Economic Forum in Davos.

Of 132 countries whose environments were surveyed, India ranks dead last in the ‘Air (effects on human health)’ ranking. The annual study, the Environmental Performance Index, is conducted and written by environmental research centers at Yale and Columbia universities with assistance from dozens of outside scientists. The study uses satellite data to measure air pollution concentrations.

Authorities in China's notoriously smoggy capital have announced that they will start publishing more accurate data on air pollution this month, bowing unexpectedly to a social-media campaign driven by the U.S. Embassy publishing its own data via Twitter.

A woman walks past the China Central Television building in December as a dark haze hangs over Beijing.

More than a million people in the Los Angeles region are exposed to undisclosed, unhealthy levels of air pollution every day, according to a lawsuit filed today by Physicians for Social Responsibility-Los Angeles, the Natural Resources Defense Council (NRDC), and Communities for a Better Environment.

Beijing environmental authorities have caved to public pressure on air pollution in a sign of the growing power of social media to influence public policy in the country.

The Beijing Municipal Environmental Protection Bureau will grant public access to air-quality readings that take into account smaller and more-dangerous pollution particles before the Spring Festival holiday begins on Jan. 23, the state-run Xinhua news agency reported Friday.

China’s Ministry of Environmental Protection had previously said such data would be released nationwide by 2016.

Air pollution levels will be monitored at as many as 14 locations in the city this Bhogi by Tamil Nadu Pollution Control Board (TNPCB).

This would be five more than last year and the decision to increase the number of locations was taken in view of expanded Chennai Corporation limits. Ambattur, Tiruvottiyur, Perungudi figure in the list of new locations. The details of TNPCB's measures, mainly by creating awareness, to prevent burning of waste during Bhogi were announced here on Wednesday by its senior officials and Environment Minister B.V.Ramana.