Mumbai, Jan 19 (PTI) Police detained at least 30 sweepers and sanitation workers on Wednesday for holding a protest near the new administration building of Mantralaya, the state secretariat here, an official said.The protest was organised by the coordination committee of sweepers and sanitation workers, he said.The police detained 10 women and 20 men for the protest, the official said, adding that they were taken to Marine Drive police station in south Mumbai.Police have deployed adequate 'bandobast' outside the Mantralaya, he said.