Beijing plans to replace its oil-burning buses with new models powered by electricity or natural gas by 2017 to reduce air pollution, Reuters reports.

The Chinese capital will buy about 14,000 greener buses to replace two-thirds of Beijing’s bus fleet and halve carbon emissions.

Air pollution in Beijing hit record levels in January, measuring 38 times the level recommended by the World Health Organizations, Reuters reports.

Earlier this month air pollution in Shanghai delayed or cancelled hundreds of flights. The poor air quality on Dec. 6 also caused the Shanghai government to issue the highest level of public health warning as the Chinese city’s pollution index ranged between 23 times and 31 times the recommended levels.

The incident happened just days before EPA administrator Gina McCarthy arrived in China to discuss US-China cooperation on air quality, climate pollution and environmental issues.