Prime Minister Narendra Modi made the pledge at the Glasgow conference.
This is the first time the country has made such a commitment.
Net zero, or becoming carbon neutral, means not adding to the amount of greenhouse gases currently in the atmosphere.
In contrast, China has announced plans for carbon neutrality by 2060, while the US and EU aim to hit net zero by 2050.
But its huge population means its emissions per capita are much lower than other major world economies. India emitted 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.
Mr Modi made the pledge as one of five commitments from his country.
They include a pledges 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, Mr Modi seems to have impressed people back home.
The BBC's Vikas Pandey reports that the prime minister appears to have found the middle ground for his base - he is seen as being serious about climate change but without compromising India's economic potential.
Most headlines are using words like "big" and "major" to describe the announcement, our correspondent reports.