India’s core industrial sectors recorded a series-high growth rate of 7.9% in September, driven by strong performances in coal, electricity, steel and refinery products.While the data points to a welcome industrial uptick, concerns remain about how sustainable the momentum will be. Much of the growth appears linked to temporary factors such as increased power demand during the heat wave and higher refining activity driven by imported oil.With global crude prices rising, foreign exchange pressures mounting and infrastructure spending continuing to shoulder much of the growth burden, economists are questioning whether the current surge can be sustained in the coming months.