Medical workers surrounded by large blocks of ice collect swab sample from a resident in an outdoor sampling site undertaken by Henan Cancer Hospital in Zhengzhou, Henan province, Aug 2, 2021. (Photos: Ecns.cn)

Medical workers surrounded by large blocks of ice collect swab sample from a resident in an outdoor sampling site undertaken by Henan Cancer Hospital in Zhengzhou, Henan province, Aug 2, 2021.

Medical workers surrounded by large blocks of ice collect swab sample from a resident in an outdoor sampling site undertaken by Henan Cancer Hospital in Zhengzhou, Henan province, Aug 2, 2021.

Medical workers in protective suits enjoy the cool summer by holding ice in an outdoor sampling site undertaken by Henan Cancer Hospital in Zhengzhou, Henan province, Aug 2, 2021.

Medical workers in protective suits enjoy the cool by cold drink in an outdoor sampling site undertaken by Henan Cancer Hospital in Zhengzhou, Henan province, Aug 2, 2021.

Medical workers eat used ice blocks as table for lunch during the break in an outdoor sampling site undertaken by Henan Cancer Hospital in Zhengzhou, Henan province, Aug 2, 2021.

Medical workers lay down on the ice blocks during the break in an outdoor sampling site undertaken by Henan Cancer Hospital in Zhengzhou, Henan province, Aug 2, 2021.

Medical workers in protective suits enjoy the cool summer by sitting on the ice blocks in an outdoor sampling site undertaken by Henan Cancer Hospital in Zhengzhou, Henan province, Aug 2, 2021.