India, May 20 -- Mango showers, or pre-monsoon downpours, are not uncommon in Bengaluru. What the city is now getting familiar with, however, is the havoc in its wake that has made headlines over the past few years. Flooded apartment complexes, drowned roads, drifting vehicles, and casualty counts - three persons died in the downpour on Monday - have displaced the happy recounting of cooling showers that made Bengaluru summers tolerable, and even pleasant.

Across expert diagnoses, two reasons for this have consistently stood out. The first is the rapid urbanisation that has contributed to the horizontal sprawl of the city, at the cost of its network of raja kaluves and lakes (raja kaluves are intra-city natural and man-made channels that...