Police used teargas and fired in the air to disperse the mob after a large number of people gathered and blocked the Ghaziabad-Greater Noida Expressway on National Highway (NH) 24, officials said.

Earlier, on the instructions of the cabinet secretary, the Noida, Greater Noida and Ghaziabad administration launched a drive to raze illegal constructions along the Hindon river.

According to officials, no construction is allowed within 400 metres of the main stream of the river but land grabbers had sold plots to people who had built houses without any approval from the authorities.

These illegal structures had created hindrances in the construction of the expressway, so the joint team of irrigation department and district administration had launched the demolition drive, officials said.