This happens in all other railway tunnels located on the upcountry line as well.
Nearly one km in length, Singimale tunnel is the longest railway tunnel in the country and has hundreds of thousands of swift nests built on its insides.
People of the area say the racketeers use bamboo ladder to reach and pluck the swift nests during nighttime.
Buyers come to Hatton from other parts of the country for these swift nests, which are made into a soup and sold at a high price to tourists.