People avoid the heat in an air-raid shelter in Chongqing. (Photo: China Daily)

Liquor is stored in an air-raid shelter in Chongqing.

People visit a museum in an air-raid shelter in Chongqing on Sept 3, 2019.

People read books in an air-raid shelter to avoid the heat in Chongqing on Sept 3, 2019.

People enjoy hotpot in an air-raid shelter in Chongqing, Southwest China, on Oct 7, 2018. The air-raid shelters, once used to protect Chongqing residents from air attacks during wartime, have become an ideal place to escape from the scorching heat. (Photo: IC)

People read books in an air-raid shelter to avoid the heat in Chongqing on Sept 3, 2019.

People read brochures about emergency precautions in an air-raid shelter in Chongqing on Sept 3, 2019.

A gas station in an air-raid shelter is seen in Chongqing.

People enjoy hotpot in an air-raid shelter in Chongqing on Oct 7, 2018. (Photo:IC)

People visit a museum in an air-raid shelter in Chongqing on Sept 3, 2019.