Prime Minister Narendra Modi made the pledge, the first time India has established a net zero target, at the Glasgow summit.
Net zero, or becoming carbon neutral, means not adding to the amount of greenhouse gases in the atmosphere.
The Indian leader is one of more than 120 leaders to have gathered in Glasgow for the two-week conference.
Dozens gave speeches on Monday laying out goals to tackle the climate crisis, consisting of UK Prime Minister Boris Johnson, US President Joe Biden and UN Secretary General António Guterres.
India is the world's fourth biggest emitter of carbon dioxide after China, the US and the EU.
But its huge population means its emissions per capita are much lower than other major world economies. India released 1.9 tonnes of CO2 per head of population in 2019, compared with 15.5 tonnes for the US and 12.5 tonnes for Russia that year.
PM Modi made the pledge as one of five
commitments from his country. They comprise a promise for India to get 50% of its energy from renewable resources by 2030, and by the same year to reduce total projected carbon emissions by one billion tonnes.
While the 2070 net zero target may have disappointed activists and experts in Glasgow, PM Modi seems to have impressed people back home.
India had "clearly put the ball in the court of the developed world" by announcing 500 gigawatts (GW) of non-fossil electricity capacity, half of energy from renewables, a reduction of emissions by one billion tonnes and emissions intensity of the GDP by 45% by 2030, according to Arunabha Ghosh, Chief Executive Officer of the Council on Energy, Environment and Water, a leading climate think tank.
"This is real climate action. Now India demands $1tn (£722bn) in climate finance as soon as possible and will monitor not just climate action but also climate finance," Dr Ghosh stated.
India's Prime Minister Narendra Modi used most of his time in front of his fellow world leaders to underline the need for lifestyle changes as the greatest solution to climate change.
But Mr Modi preserved his biggest news to the last minute.
Detailing what he termed were India's "five elixirs" for climate, Mr Modi proclaimed that his country would adopt a net zero emissions target - by 2070.
This is quite a substantial step for the world's third largest emitter, still getting more than 50% of the country's electricity from coal.
It has to be tempered by the fact that the date is far past the mid-century goal for carbon neutrality that scientists say is necessary to avert the most dangerous levels of warming.
But there has been a general welcome for the goal.
