Tourists visit the Caka Salt Lake scenic area in Caka Town of Wulan County, northwest China's Qinghai Province, April 26, 2020. Caka Salt Lake scenic area on Sunday reopened to the public in an orderly manner with strict measures taken to fight against COVID-19. (Photos: Xinhua/Zhao Yuhe)

Tourists visit the Caka Salt Lake scenic area in Caka Town of Wulan County, northwest China's Qinghai Province, April 26, 2020. Caka Salt Lake scenic area on Sunday reopened to the public in an orderly manner with strict measures taken to fight against COVID-19.

Photo taken on April 26, 2020 shows a view of the Caka Salt Lake scenic area in Caka Town of Wulan County, northwest China's Qinghai Province. Caka Salt Lake scenic area on Sunday reopened to the public in an orderly manner with strict measures taken to fight against COVID-19.

Tourists visit the Caka Salt Lake scenic area in Caka Town of Wulan County, northwest China's Qinghai Province, April 26, 2020. Caka Salt Lake scenic area on Sunday reopened to the public in an orderly manner with strict measures taken to fight against COVID-19.

Tourists visit the Caka Salt Lake scenic area in Caka Town of Wulan County, northwest China's Qinghai Province, April 26, 2020. Caka Salt Lake scenic area on Sunday reopened to the public in an orderly manner with strict measures taken to fight against COVID-19.