China’s capital Beijing, regularly shrouded in hazardous air pollution, plans to replace its oil-burning buses with greener models by 2017 to help clear the smog, state news agency Xinhua said.

Nearly 14,000 new buses powered by electricity or natural gas will be bought to replace two-thirds of Beijing’s bus fleet and halve carbon emissions, Xinhua said on Thursday, citing the city’s environment and transportation authorities.

Air pollution in Beijing hit unprecedented levels in January when an index measuring particulate matter with a diameter of 2.5 micrometers (PM2.5) shot up to a staggering 755 - 38 times the level recommended by the World Health Organisation.

China’s worsening air quality is a result of it chasing economic growth at all cost in the past 30 years, a pursuit that turned it into the world’s second-biggest economy, but which also poisoned much of its air, water and soil.

Rising public concern over the health dangers of China’s air pollution has worried its stability-obsessed leaders, who fear the issue may become a rallying point for wider dissatisfaction.

China has adopted an emergency response program to try to reduce the pollution, including alternating days for cars with odd and even license plates to be on the road and closing schools when the smog is particularly heavy.