An archipelago known for its Buddhist temples, the Tibetan capital and a seaside city known for corrupt real estate deals, are the only three cities in China to meet national air quality standards, in a stark illustration of how pervasive pollution has become in the world’s most populous country.

Unrelenting smog – including a week-long stretch last month of “hazardous” air in Beijing – has become a focus for public discontent, particularly in prosperous urban areas. Last week, Li Keqiang, China’s premier, told the annual meeting of the country’s legislature that his government would wage “war on pollution”.

Haikou, the capital of sub-tropical Hainan Island, Zhoushan – an archipelago just south of Shanghai that consists of 1,390 islands and 1.1 million people – and Lhasa, the capital of Tibet, were the only three to meet national standards in a survey of 74 of the nation’s largest cities, vice-minister of environmental protection Wu Shaoqing told journalists at the wekend.