Parameswaran Iyer, who has been appointed NITI Aayog's next CEO, voluntarily retired from IAS to join the World Bank in 2009. In 2016, PM Narendra Modi chose Iyer to lead the flagship Swachh Bharat Mission. The 63-year-old resigned from his post at Department of Drinking Water and Sanitation in 2020 and returned to US to join the World Bank.