China's National Health Commission said it was investigating a hospital in the southwest megacity of Chongqing for its alleged involvement in surrogacy, which is illegal in China, after wide circulation of the issue on social media. The incident comes after a series of official investigations last year related to the issuance of fake birth certificates at a time when China is trying to boost its birth rate. Chongqing Angel Obstetrics and Gynaecology Hospital has been cooperating with illegal surrogacy agencies, a post on Chinese social media platform Weibo said on Sunday.