A map showing people where to donate their hair for children with leukemia who need a wig after receiving chemotherapy was released in Shanghai on Tuesday.

The first of its kind in the city, the map designates 25 barbershops where people can donate their hair and in return get a certificate recognizing the donation.

The map was released by Children's Hospital of Shanghai and the Shanghai Hair and Beauty Trade Association.

"It will be an efficient approach to make sure wigmakers always have enough real hair to manufacture wigs for children," said Niu Jun, director of the social work department at the hospital.

The hospital launched the hair donation program three years ago for young patients with leukemia. On Tuesday, 100 volunteers, most of whom were college and high school students, donated their hair.

Thirty hairdressers sent by the Shanghai Hair and Beauty Trade Association collected the volunteers' hair at a local school. It will be turned into wigs by a manufacturing company.

This is the third year for the hair donation program at the hospital. A total of 166 volunteers have donated hair, and 15 children at the Shanghai children's hospital have received free wigs.

"A wig made of real hair costs up to 10,000 yuan ($1,500). The program is simply a call to all people and sectors to help offer free wigs to children who are afraid of playing with others due to hair loss," Niu said.

The number of volunteers has soared from eight in 2016 to 100 this year, he said.

To encourage donations, the hospital is building an online platform where people can check their donation record or whether their hair has been used for a wig, Niu said. They can also see who received the wig.

The hospital has also set up a fund along with the Hongyi Poverty Alleviation Foundation to raise money for wigs for children with leukemia.

Huang Yan, 18, from Shanghai Caoyang No 2 High School, was among those who donated.

"It was a memorable experience for me, and is about becoming an adult who will take on more responsibility in helping the community," Huang said.

Ding Jianshu, Party chief at the Children's Hospital of Shanghai, said they hope patients also feel the love from the community while undergoing therapy, which can be physically and psychologically challenging.

"We are waiting for more hospitals to join us," Ding said.