When she first volunteered for a rural bridge-building project in Gansu province three years ago, Cheryl Cham Suet-ying fainted from the stifling summer heat.
That hasn't deterred the civil engineering student from returning to the mainland this summer on a similar venture.
'I felt so bad because instead of helping I was being attended to,' Cham says of her baptism as a helper. 'I volunteered because I wanted to do something for the villagers. I saw how accidents can occur when crossing the river - for example, a mother and child at Maosi [site of the first bridge] were swept away a few years ago.'
This year, however, the 22-year-old is leading a University of Science and Technology student team, which has designed a bridge to enable farmers in a Sichuan village to safely reach their fields even when melting snows or heavy rains can raise river levels up to 12 metres. Instead of just being one of the volunteers, Cham now bears heavier responsibilities.
'This time I have to co-ordinate, solve problems and take decisions on design. I realise there is a lot to do before we can begin construction,' she says.
Cham and her team form a cornerstone of the Wu Zhi Qiao Charitable Foundation. Set up last year, the charity recruits Hong Kong students to help mainland villages lacking a safe river crossing. The volunteers design simple bridges that they also construct in collaboration with villagers and mainland university students.