A traffic warden in Mumbai has been arrested for allegedly assaulting documentary filmmaker and winner of the Green Oscar award, Nikhil Niranjan Alva.

Nikhil is the son of Margaret Alva, Congress party in-charge for Maharashtra.

According to Nikhil's statement recorded at the Andheri police station, he was travelling on the Western Express Highway on Sunday when he saw warden Lavkush Duby beating up a taxi driver.

The taxi driver had jumped a traffic signal.

Nikhil started recording the altercation with his camera phone, the statement says.

When Duby saw Nikhil recording his activities, he went to him and assaulted him.

An assistant inspector, a head constable and a constable were present nearby but they did not interfere.

By then state Medical Education and Higher and Technical Education Minister Suresh Shetty had been informed about the incident and he reached the spot.

A case was later registered against Duby under section 323 (voluntarily causing hurt) of the Indian Penal Code, section 341 (wrongful restraint), and section 506 (criminal intimidation) and the warden was arrested.

Sources close to Alva on Wednesday denied that he uses a camera phone.

"It is a high profile case. Top officers have requested that the assistant inspector, head constable and the constable be suspended for not taking any action against the warden," a police source said.