The team has visited Mayapuri following reports that radiation exposure was still high in the area.
"The team began the decontamination process Sunday afternoon," said a spokesperson of the environment organisation Greenpeace.
The experts held a meeting late Saturday with the scrap dealers of Mayapuri where the first radiation leak was reported last month. One person died due to radiation exposure.
Greenpeace in its investigation Friday found that Mayapuri was "not a safe zone for human beings".
"The investigation has identified hotspots with more than 5,000 times natural background radiation," an official said.
The Greenpeace team observed that it was a matter of concern that the identified six hotspots remained despite AERB having declared the area safe.
Police said the source of the leak last month was a radioactive Gamma Cell containing Cobalt-60, auctioned as scrap by Delhi University's chemistry department over two months ago.
Six people exposed to the radioactive Cobalt-60 are still undergoing anti-radiation treatment in a hospital.
