Deflation refers to a sustained reduction in the overall price level, while disinflation is a slowdown in the inflation rate even if prices remain positive. Deflation is caused by a fall in aggregate demand, creating a deflationary spiral as consumers delay purchases and lower economic activity. This can be countered by monetary policies to boost demand through lower interest rates or increasing the money supply. While India is experiencing disinflation currently, its strong GDP growth makes deflation unlikely as long as growth remains high and the government has tools to stimulate the economy if needed.