Industrial output growth slowed sharply in September to 4.4% compared with 8.2% in the same month of last year, government data showed on Friday.
The output from factories, mines and utilities in Asia's third-largest economy was well below forecasts by economists, who had expected a rise of around seven percent from a year earlier.
The Indian production was also far below rival China's industrial output, which expanded 13.1% year-on-year in October, according to figures released this week.
The Indian figures marked the second month in a row that industrial output has disappointed financial markets. Output rose just 5.6% year-on-year in August, a sharp decline from a 15.2% surge the previous month.
Industrial output had been lifted by government spending and aggressive monetary easing to help shield the economy from the global economic crisis.
But those measures are being unwound by sharp monetary tightening as India's economy has shown signs of bouncing back from the international economic slump.