With Mumbai receiving poor rainfall in catchment areas in 2009, the Brihanmumbai Municipal Corporation has been carrying out cloud seeding operations over the lakes that supply water to the city.

The lakes that supply drinking water to Mumbai are Bhatsa, Upper Vaitarna, Modak Sagar, Tansa, Vihar and Tulsi.

Cloud seeding is the process of spreading silver iodide aerosols or dry ice into the upper part of clouds to try to stimulate the precipitation process and form rain.

Since most rainfall starts through the growth of ice crystals from super-cooled cloud droplets (droplets colder than the freezing point) in the upper parts of clouds, the silver iodide particles are meant to encourage the growth of new ice particles.

However, according to media reports, the tests have so far not yielded the desired results.

Out of the four cloud seeding experiments carried out at Tansa lake between August 7 and 9, only one that was undertaken on Friday resulted in 16 mm rainfall over Modaksagar dam, the Indian Express reported.

Image: Cloud-seeding experiment in progress over the Tansa lake.

Photograph: Sahil Salvi