A wall at Delhi's Qutub Complex, a world heritage site, collapsed due to the accumulation of drainage water. Unauthorised colonies without functional drainage system weakened the structure and the wall collapsed with the drainage water overflowing, and pushing the wall. As the drainage water accumulates in the lawns of Qutub Complex, no measure has been taken by the civic body. No construction is allowed within 300 m of the historical sites, conserved by Archeological Survey of India.