A public air-raid shelter in Hangzhou which can provide coolness to nearby residents. [Photo provided to chinadaily.com.cn]

Temperatures inside these shelters, which have a combined holding capacity of 2,000 people, can be 10 degrees lower than the outside, luring residents and tourists to flock in for relief.

Inside the air-raid shelters, one can find daily necessities such as water, electricity, tables, chairs and free WiFi, as well as heatstroke prevention medicine and other essential supplies.

"I came here with my friends and this is a perfect place for reading books during summer time," said Wang Yitin, a post-graduate student in Hangzhou who is staying at a shelter at the Shiwukui alley located around the West Lake.

In addition to Hangzhou, other cities in Zhejiang such as Taizhou, Lishui and Zhuji have also opened such shelters to the public.