MUMBAI, India — As this city prepared recently to inaugurate a shiny new bridge that officials promise will ease Mumbai’s chronic traffic jams, Dilip da Cunha was peering at the underbelly of the city’s waterways and drainage systems.
Taking two visitors on a tour of the busy causeway where the city’s befouled Mithi River meets the Arabian Sea near the new bridge, the Bandra-Worli Sea Link, he pointed out a small clump of trees nearby under which several men were defecating.
The trees represented one of the last remaining species of the mangroves that once dominated the ecology of Mumbai, India’s financial capital and its most populous city. Over the decades, most of the wetlands of the Mithi River estuary that were home to such trees have given way to highways, slums, office buildings and apartment towers.
While the mangroves’ retreat has provided valuable acreage for Mumbai’s growth, Mr. da Cunha, who is one half of a husband-and-wife team that recently finished an exhaustive study of the city’s landscape, said their disappearance, along with the degradation of the city’s waterways, has made the city increasingly vulnerable to flooding during the monsoons.