People cool off at a rest area opened to the public to escape heat in Hangzhou, Zhejiang province, on Thursday. [Photo by Li Zhong/For China Daily]

As China enters sanfu — the three 10-day periods on the Chinese lunar calendar that are expected to be the hottest of the year — some major cities have devised creative ways to help residents keep cool.

In Chongqing, for example, the subway operator has set up rest areas inside 113 stations, which are kept around 25 C, ideal havens from the heat. These areas are located in quiet corners of the spacious stations. Each one is equipped with chairs, water dispensers and a first-aid kit, and anyone nearby, not just passengers, can come inside to cool off.

"We provide help for people overcome by the heat," said Zhan Yan, a subway station manager in the city. "We have medicated oil and traditional Chinese medicines for heatstroke."

People using the rest areas can ask station staff members for help at any time, Zhan added.

The facilities are especially welcomed by seniors and people who work outdoors such as delivery and sanitation workers.

"I will come here every day after lunch," said Liu Xuequn, a 66-year-old resident who lives near the Fuhua Road station.

"It is very comfortable here. Also, air-conditioning at home is really expensive, so I can save a lot of money this way."

One of China's so-called three stoves, Chongqing experiences some of the country's hottest weather in summer. Temperatures as high as 42 C are forecast for many parts of the city in the coming days, making the rest areas all the more enticing.

Chongqing is not alone. With scorching heat waves coming across the country, cities in East China's Zhejiang province have also adopted cooling measures.

Hangzhou, the provincial capital, issued its first red alert for heat on Wednesday, as the peak temperature at noon topped 39 C.Since late June, the city has gradually opened multiple free cool spots to the public — in subway stations and wartime bomb shelters — where residents can escape the scorchers.

Hangzhou has opened six of these underground shelters to the public. They'll be open for nine hours daily over the next two months.

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

Inside, one will find welcome amenities — water, electricity, ping-pong tables, chairs and free WiFi, as well as heatstroke prevention medicines and other essential supplies.

"I came here with my friends," said Wang Yiting, a graduate student in Hangzhou who was taking advantage of a shelter in Shiwukui Alley near West Lake.

"This is a perfect place to read a book on a hot summer day."