India, April 29 -- Smoke is an aerosol; aerosol particles help form clouds; clouds bring rain.

Havans (traditional fire rituals) create smoke.

So far, so good.

That could explain why a group of scientists is engaged in an exercise to determine the efficacy of havans in bringing rain.

Scientists from the Madhya Pradesh Council of Science and Technology and Scientific Council, Indian Institute of Technology, Indore, and Indian Institute of Tropical Meteorology (IITM), have started a research project to find whether Som Yagya, a havan in which juice of a medicinal plant Samovalli (Sarcostemma brevistigma, a kind of oleander) is offered to the fire can purify the environment and promote cloud condensation , bringing about rain.

On April ...