The RBI highlighted the need to boost domestic growth due to headwinds "on the global front".
"The need is to strengthen domestic growth impulses by spurring private investment which has remained sluggish," the RBI wrote in the policy statement.
The underperforming economy could hamper Prime Minister Narendra Modi's prospects of getting re-elected for a second term in a looming general election.
While the central bank projected retail inflation at 3.8 percent by January-March 2020 - within its target of 4 percent - it also warned of the upside risks to price pressures if food and fuel prices rose abruptly, or if fiscal deficits overshot targets.
Annual consumer inflation was just 2.57 percent in February following five months of deflation in food prices.
The RBI lowered its economic growth forecast to 7.2 percent for the 2019/20 April-March fiscal year, from the February view of 7.4 percent.
Sluggish private investment and a weakening rural economy pulled India's economic growth down to 6.6 percent in the December quarter, its slowest in five quarters, while the unemployment rate hit multi-decades high.
Voting starts next week, but the result will only be known on May 23 and uncertainty over which party will lead the next government has complicated the Reserve Bank of India's task. It cannot be sure of the government's fiscal plans, as the major parties made promises for heavy spending during their election campaigns.
"Should there be a fiscal slippage...this could crowd out private investment, impact potential output, and result in higher inflation," the RBI said in a separate monetary policy report.
India's financial markets were little changed after the policy decision.
The 10-year benchmark bond yield rose to 7.46 percent from 7.37 percent before the decision and the rupee strengthened to 68.78 to the dollar from 68.82 before.
The broader NSE stock index was down 0.18 percent at 11,622.35 points.