News: A slowdown in the Indian economy has resulted in an oversupply of office space in the country's top cities. This has further led to an increase in vacancy rates that have prompted some developers to build offices into residential buildings. Demand for offices in the country's top seven cities, including Mumbai, Hyderabad and Bangalore, has declined to the lowest level in around two years in the three months to September 30. Vacancy rates in Mumbai and New Delhi were more than 20% in Q313, the highest in Asia after Chengdu, China, according to realty consultant Cushman & Wakefield. Six Indian cities featured in the list of top 10 office markets with the worst vacancies in the region, according to Cushman.