The devices can disrupt mobile signals up to 50 meters.
Two illegal Chinese jammers were found at a shop in Delhi's Palika Bazaar on Saturday, posing a threat to security and violating Centre's guidelines prohibiting its use or sale by unauthorised people. The police have arrested the shop owner, identified as Ravi Mathur, as he did not have a license and documents to sell the devices.
As per Centre's rules, the Chinese jammers can only be used by authorised government and defence officials with specific license and documentation.
According to Mathur, he bought the jammers from Lajpat Rai Market in Delhi for Rs 25,000, and was aiming to sell it at a higher price.
The devices - which can disrupt mobile signals up to 50 meters - had jammed all cellular activities in the vicinity, including incoming and outgoing calls, and SMS. The jammers forced all the calls that were already in progress to be disconnected and the phones showed a "no network" sign.
In cases of crime, the police would not be able to track what communication took place at the spot due to the jammers.
The Delhi Police have informed the Telecommunication Department regarding the incident, officials said.
They are also carrying out searches in other markets in the national capital, they added.