A worker cleans the glass curtain wall of a skyscraper in Zhengzhou, capital of Central China’s Henan province, May 2, 2019. [Photo/Xinhua]

Aerial photo taken on May 2, 2019 shows workers cleaning the glass curtain wall of a skyscraper in Zhengzhou, capital of Central China’s Henan province. [Photo/Xinhua]

A worker cleans the glass curtain wall of a skyscraper in Zhengzhou, capital of Central China’s Henan province, May 2, 2019. [Photo/Xinhua]

Aerial photo taken on May 2, 2019 shows workers preparing to clean the glass curtain wall of a skyscraper in Zhengzhou, capital of Central China’s Henan province.[Photo/Xinhua]