The agency retained India's rating at 'BBB-' with stable outlook and expressed hope that country's economic growth would average about 8 per cent during 2015-18 period.
"We are affirming our 'BBB-' long-term and 'A-3' short- term sovereign credit ratings on India," it said.
'BBB' is the lowest investment grade rating and stable outlook reduces risk of possible sovereign rating downgrade.
The stable outlook, it said "balances India's sound external position and inclusive policymaking traditions against the vulnerabilities stemming from its low per capita income and weak public finances.
The agency also cautioned that downward pressure on the ratings could reemerge if growth disappoints (perhaps as a result of stalling of reforms), if, "contrary to our expectations, the new monetary council is not effective in achieving its targets, or if the external liquidity position of the nation deteriorates more than we currently expect".
However, it added upward pressure on the ratings could build if the government's reforms markedly improve its general government fiscal outturns and with them the level of net general government debt so that it falls below 60 per cent of GDP.
A rating constraint, S&P said is India's low GDP per capita, which "we estimate at USD 1,700 in 2015".
India's growth outperforms its peers and is picking up modestly, it added.
"Following India's early 2015 rebasing of GDP, we expect GDP growth of 7.4 per cent in 2015 (6 per cent in GDP per capita terms) and for it to average just under 8 per cent over 2015-2018 (just under 7 per cent in GDP per capita terms).
