The Central Statistics Office said on its website the general index for April was 167.3.
Manufacturing, a major component in the index, grew 2.8 percent from a year earlier, and capital goods production grew an annual 1 percent.
The Wall Street Journal said April's figures would raise new concerns about the strength of the Indian economy. It said the growth was below the median forecast of 2.4 percent among 18 economists.
In March, the growth was 3.4 percent year-on-year, revised from earlier estimate of 2.5 percent.
The Indian government already is under pressure because the economy grew only 5 percent in the past fiscal year, the slowest rate in a decade. Growing current account deficits and other factors pushed the value of the Indian rupee to record lows against the U.S. dollar this week, with some improvement seen on Wednesday.