Kumar will replace incumbent Arvind Panagariya who is leaving the government think tank on August 31.
"Overall tax burden on the economy has come down after the implementation of the Goods and Services Tax (GST)," he said at an event organised by 'PAHLE INDIA FOUNDATION'.
The nationwide GST was rolled out on July 1, overhauling India's convoluted indirect taxation system and unifying the USD 2 trillion economy with 1.3 billion people into a single market.