MUMBAI, March 14 (Xinhua) -- Indian telecom service providers have asked e-commerce companies such as Amazon, Flipkart and Snapdeal to immediately stop the sale of mobile signal boosters as they cause network interference and impact quality of service to end consumers, according to local media Mint news on Thursday.

In a letter addressed to e-commerce companies, Cellular Operators Association of India (COAI), an industry body, pointed out that under the Indian Wireless Telegraph Act, 1933, possession and sale of such equipment without a license from the department of telecommunications is a punishable offence.

Mobile signal boosting equipment are used in high density population areas, putting pressure on the already congested mobile network, according to the Mint news report.

In December last year, India's telecommunication minister Manoj Sinha, in a written reply to the lower house of the parliament, informed that few e-commerce companies have been directed to ensure compliance with statutory norms as they were found to be dealing with "unauthorized" wireless equipment, including boosters.