A young woman is fighting for her life after falling into scalding water when a section of pavement collapsed on a Beijing street.

Yang Erjing, 27, was walking on Beilishi Road in Xicheng district on Sunday when the ground gave way and she fell into 90 C water, which had leaked from underground heating pipes.

Local residents had reported steam rising from the pavement earlier and pipe repairs were already under way further along the street.

Yang, a clothing store manager and mother of a 7-month-old child, was rushed to Jishuitan Hospital, where, on Wednesday, she was reported to be in a deep coma, suffering serious burns to 99 percent of her body.

An investigation has been launched by Xicheng district's work safety bureau and other departments, including Beijing District Heating Group, which operates the city's trunk pipelines and was carrying out repairs near the accident scene.

Workers repair hot water pipes on Beilishi Road in Xicheng district, Beijing, on Monday, where a woman fell into scalding water on Sunday.