Besides Mannar and Vavuniya, the Indian companies also cleared mines in Batticaloa in the east. Horizon also worked in the neighbouring districts of Trincomalee and Amparai.

All de-mining is done under the care of the National Steering Committee, a government body in Colombo.

After Sri Lanka crushed the Liberation Tigers of Tamil Eelam (LTTE) in May this year, the Indian government also decided to provide separate funds to Horizon and Sarvatra as part of stepped up aid to the island nation.

The 82 Indians who have gone now are an outcome of the Indian funding.

Both Indian companies have shared their skills with Sri Lankans they have employed over the years.

It wasn't easy though when it all began.

'There were lots of problems in the beginning,' said Puri, referring to the 2003 period when the Norway-sponsored ceasefire brought a semblance of peace to Sri Lanka. The LTTE then effectively controlled the northeast.

'LTTE people were initially suspicious. They wanted to know why (retired) Indian Army people were in Sri Lanka,' he said.

The suspicion arose from months of fighting between the LTTE and the Indian Army in Sri Lanka's northeast in 1987-90.

In the absence of records, there was no clear idea where exactly the mines had been laid. And since this was humanitarian de-mining, extra care had to be taken, making it more time-consuming and difficult.

How long will it take for Sri Lanka to be cleared of mines?

According to Pitre, it will take one-and-a-half to two years to do away with most landmines and another year to declare the areas safe for habitation.

Added Puri: 'From a distance it might seem as if we are working slowly. That is not so. We have to clear every bit of land carefully, inch by inch. It is a meticulous operation.'