A 64-year-old Hong Kong hiker remains in critical condition this week after she collapsed on Tung Ping Chau in Tai Po in the New Territories on Sunday.

The woman and her husband, 68, were with 20 people when they went on a hike on the island, Sing Tao Daily reported. When they arrived at a beach near Kang Lau Shek at around noon, Wong collapsed due to a heat stroke. The group’s leader called the police.

Wong was airlifted to Pamela Youde Nethersole Eastern Hospital by a Government Flying Services helicopter. Her friend, 64, also felt unwell but declined hospital treatment.

According the Hong Kong Observatory, temperatures reached 31 degrees Celsius in Tai Po on Sunday with relative humidity at 85%, while the temperature in other districts reached 32.5 degrees.

In a separate case, a 69-year-old cleaner collapsed because of heat stroke at the Hong Kong Wetland Park in Tin Shui Wai, Yuen Long. She recovered in hospital, Oriental Daily reported.