The growth rate of eight infrastructure sectors had stood at 6.9% in November 2017New Delhi:Output in eight core industries grew at at 3.5 per cent in November, its slowest pace in 16 months, due to a fall in crude oil and fertiliserproduction, official data showed on Monday.The lowest expansion in output growth of these key industries was last recorded in July 2017 at 2.9 per cent.The growth rate of eight infrastructure sectors -- coal, crude oil, natural gas, refinery products, fertilisers, steel, cement and electricity -- was 6.9 per cent in November last year.Crude oil and fertiliser production recorded negative growth of 3.5 per cent and 8.1 per cent, respectively, as per government data released Monday.The growth rate in production of natural gas, refinery products, steel, and cement sectors slowed to 0.5 per cent, 2.3 per cent, 6 per cent, and 8.8 per cent in November, respectively.Slow growth in key sectors would also have implications on Index of Industrial Production (IIP) number as these segments account for about 41 per cent to total factory output.However, growth in coal and electricity output grew by 3.7 per cent and 5.4 per cent in November as against 0.7 per cent and 3.9 per cent, respectively in corresponding period last year.During April-November this fiscal, eight core sectors free by 5.1 per cent as against 3.9 pet cent during same period last fiscal.