Seven tonnes of mangoes and 2 kg of papaya worth nearly Rs 5 lakh were seized on Monday, from the Koyambedu market in Chennai.

Police also found 3 kg of an artificial ripening agent - ethylene and disposed of fruits worth Rs 4.8 lakh in the Koyambedu bio-methanisation plant, according to a TOI report.

In the 4-hour long raid which started at 4am on Monday, the police checked 44 shops out of which 39 were found to be using artificial ripeners in their fruits.

While 15% of the shopkeepers use artificial ripening agents, the rest use ripening chamber to mature the fruits.

To ripen mangoes, shopkeepers leave packets of ethylene for a few hours after shops close for the night. They remove them after a few hours and the mangoes would have ripened, police officers told TOI.

For papayas, baking soda is mixed in a 20-litre container of water and the fruits are exposed to the escaping carbon dioxide in the holes in the container, the officials added.

The shopkeepers admitted that they used artificial agents but denied that these artificial agents caused heath problems.

"We have not heard of side effects," the report added. However, agents are known to cause several problems such as heartburns, indigestion and nausea.

They also urged the government to provide artificial ripening chambers so that they do not have to resort to agents such as ethylene.