Thomson volunteered to protest against the overexploitation of ground water in Plachimada between 2000 and 2005 by Hindustan Coca–Cola Beverages Private Limited (HCBPL). Now he is in his final stages of submitting his thesis 'Commercialisation of water: A study on developmental issue and ecological concerns.'

He told Newsline: "There are two kinds of compensation, which a company can provide. One is the cost price, which is basically what a company can give to its employees as well as shell out for the raw materials being used. The second is an external cost, which might also have a negative impact on environment and the ecology of the area. This cost is not payable and can have a negative impact. The reason: it may also affect generations of people living in the area where an MNC has come up."

Plachimada, which was dominated by the tribals, had HCBPL consuming around 5 lakh litres of ground water daily. People argued that the MNC was contaminating water by 13 to 15 lakh litres from 16 bore wells daily, said Thomson who also volunteered to survey this area with Dr P R Sreemadevan Pillai, the author of the book, The Saga of Plachimada.

He said several uncommon diseases started emerging in Plachimada whose ground water had rich cadmium, chromium, manganese and sulphide more than the prescribed norms and regulations. There were reports of people being affected by diseases like hair fall to even asthma, he said. He added that HBPCL finally closed down its production in Plachimada in 2005 due to rising protests.

Thomson said his study is divided into three parts: Plachimada before the MNC came up, the impact and the situation after the closure.