Photographs of a smog-wreathed Tiananmen Square and the iconic headquarters of China Central Television dominated reports of Chinese pollution last year, but analysis shows nine other Chinese cities suffered more days of severe smog than the capital in 2013.

The worst was Xingtai, a city of more than 7 million people south-west of Beijing, which was hit by 129 days of "unhealthy air" or worse – the threshold at which pollution is considered at emergency levels – and more than twice as many days as the capital experienced.

Heavy pollution surrounds the China Central Television headquarters building in Beijing. Photograph: Ed Jones/AFP/Getty Images

Beijing suffered 60 days of pollution above emergency levels, sparking reports of an "airpocalypse", a boom in sales of air purifiers and masks and measures to tackle the problem including the destruction of open-air barbecues and a crackdown on fireworks for Chinese new year.

Residents ride bicycles along a street amid heavy haze in Xingtai. Photograph: China Daily/Reuters

Last week, the Chinese premier, Li Keqiang, "declared war" on pollution, saying it was "nature's red-light warning against the model of inefficient and blind development."

Children walk back home after school on a severely polluted day in Shijiazhuang. Photograph: Alexander F. Yuan/AP

The new analysis by Energy Desk, a site published by Greenpeace, is based on Chinese government data of fine particulates (PM2.5s), that have been linked by studies to increases in lung cancer and heart failure. It ranked cities against the US air quality index, based on how many experienced "very unhealthy" days or worse, roughly equivalent to levels the Chinese government considers an emergency.

Fang Lifeng, Greenpeace east Asia climate and energy campaigner, said: "China's air pollution crisis usually makes the headlines when the smog cloud hits Beijing, but this research shows just how widespread this problem really is. There are now millions of Chinese people living in cities with air pollution above emergency levels for a third of the year, while other urban areas have gone a whole 12-month period with hardly any days of good-quality air."

Most of the cities in the top 10, including Shijiazhuang, Baoding, and Langfang, are in the Hebei province south of Beijing, which is home to a large number of coal-fired power plants and industries including steel and cement that burn coal. Harbin, a city north-east of Beijing, which made headlines in October due to a choking smog that forced schools and the airport to close, comes in below Beijing on the ranking, at number 17.

Beijing only had 13 days considered "good" on the US index last year, with 70 days of moderate air pollution, 64 at unhealthy for sensitive groups, 148 unhealthy days, 45 very unhealthy, 14 deemed hazardous and one day that registered at "beyond index", ie off the scale. Weather conditions in Beijing and the surrounding regions often compound the particulates generated by coal burning, cars and industry, with cold winter air trapping the pollution.

China is not the only country suffering air pollution problems, and far from the worst. Iran is home to four of the world's most polluted cities, with Quetta and Peshawar in Pakistan also in the top 10 alongside Kanpur and Ludhiana in India, data from the World Health Organisation shows.