Adding to the worries of the Government, which is battling in tandem with the Reserve Bank of India to rein in inflation, the industrial growth slumped to a six-year low of three per cent in March, mainly owing to a dismal performance by the manufacturing sector. The industrial growth data as per the Index of Industrial Production (IIP), which was released here on Monday by the Central Statistical Organisation (CSO), show that the output increase witnessed in March this year was the lowest since the 2.4 per cent growth posted in February 2002.