Why did industrial production in India increase during the First World War?

The increase in industrial production in India during the First World War was fueled by disruptions in global trade and the strategic needs of the British Empire. With British mills busy with war production to meet the needs of the army, Manchester imports into India declined. Suddenly, Indian mills had a vast home market to supply. As the war prolonged, Indian factories were called upon to supply war needs: jute bags, cloth for army uniforms, tents and leather boots, horse and mule saddles and a host of other items. New factories were set up and old ones ran multiple shifts. Many new workers were employed and everyone was made to work longer hours. Therefore, the war led to an increase in industrial production.