His direct, trenchant criticism of spiritual frauds and organized religions was enthusiastically received by audiences, initiating a new dynamism in the Rationalist movement, especially in Sri Lanka and India.

Kovoor's first assignment in Ceylon was teaching botany at Jaffna College, Vaddukoddai for 15 years until 1943.

I entrust this task to my son, Aries Kovoor, who is a professor at the Sorbonne University, Paris.

His books Begone Godmen and Gods, Demons and Spirits, about his encounters with people claiming psychic powers, are still bestsellers in India.

The challenge listed 23 miracles or feats that godmen (and Western mystics and performers such as Uri Geller and Jeane Dixon) claimed to perform, such as reading the serial numbers from currency in sealed envelopes, materializing objects, predicting future events, converting liquids from one kind to another, and walking on water.

The Sri Lankan Rationalist Association, led by Professor Carlo Fonseka, renewed the challenge in 2012 and increased the reward to one million dollars.

The first recipient was Indian film star Kamal Haasan in acknowledgment of his humanist activities and secular life.

In 2008, Punjab Chief Minister Parkash Singh Badal, leader of Shiromani Akali Dal, imposed an "immediate ban" on Kovoor's God, Demons and Spirits, translated into Punjabi by Megh Raj Mitter.