Pay Drechsel is going for his daily morning walk around Thalangama Wetland, in Sri Lanka's capital Colombo. The Sun casts a warm glow over flowering pink water lilies as a farmer scrubs down his water buffalo. A kingfisher hovers nearby. Soon, photographers will arrive to capture curved-necked egrets, waders probing for crawling worms, and little cormorants diving for freshwater fish.

Thalangama Wetland and its surrounding swamps, reedbeds, canals and rice fields teem with life. But this hasn't always been the case. About 15 years ago, these ecosystems were degraded and filled with rubbish. They were "dirty, very dirty", says Drechsel, interim country manager at the International Water Management Institute (IWMI) in Colombo

To read the full story visit https://www.bbc.com/future/article/20240917-how-sri-lanka-is-cleaning-up-wastelands-and-reviving-colombos-wetlands