The police said that the protest, which started at around 1 p.m., was attended by around 2,000 sanitation workers along with AAP MLAs.
"When the police tried to stop the protesters from blocking the road, they clashed with the police and in the process injured at least nine policemen. The Kamla Market ACP suffered fracture in the fingers," said a senior police officer.
The Delhi police later registered FIRs against four AAP MLA -- Kuldeep Monu (Kondli), Rakhi Bidlan (Mangolpuri), Akhilesh Tripathi (Model Town) and Rohit Mahroliya (Tirlokpuri) -- under various sections of the Indian Penal Code at the Kamla Market police station.