Just 25 big cities — almost all of them in China — accounted for more than half of the climate-warming gases pumped out by a sample of 167 urban hubs around the world, an analysis of emissions trends showed Monday.

In per capita terms, however, emissions from cities in the richest parts of the world are still generally higher than those from urban centers in developing countries, researchers found in the study published in the Frontiers journal.

The study compared greenhouse gas emissions reported by 167 cities in 53 countries, and found that 23 Chinese cities — among them Shanghai, Beijing and Handan — along with Moscow and Tokyo accounted for 52% of the total.