Local residents choose to stay in air-raid shelters to hide away from intense summer heat in Nanjing, East China's Jiangsu Province. /VCG Photo

The temperature inside the shelters is usually around 24 degrees Celsius. The higher the temperature outside, the colder it feels inside on hot summer days. /VCG Photo

The open-to-public shelters are equipped with dehumidifiers, water-drinking machines, tables and chairs and sometimes TVs and WIFI. /VCG Photo

Seven civil air defense works are opening in Nanjing this year. /VCG Photo