that is wrong.
Indian GDP end of 2018 is $2.72632 trillion
https://tradingeconomics.com/india/gdp
China's GDP end of 2018 is $13.6085 trillion
https://tradingeconomics.com/china/gdp
So for Indian to reach china assuming China's GDP is locked without growth and Indian GDP grows at 5% pa.
It would take indian approximately another 33 years to reach China's GDP of today.
GDP PPP
Indian 2018 = $6.8992 trillion
China 2018 = $16.1868 trillion
It will take Indian with assumption that china remains time locked and India grows at 5%. about 18.4 years.
Now if One factors in China's growth rate which is 6.9% or thereabout thus it is above Indian. It will take a lead and India will play catch all along.
People are forgetting China was export orientated economy but now it is turning towards domestic consumption based economy similar to USA. China has potential to grow for long period of time and I cannot possibly see any country catching up or overtaking China for next 50 years.