You need not to deflate IIP, it's already indexed it's in real term. You only need to take a proxy for inflation that may be consumer price index. You can look at my paper. Hope this work well.
To my knowledge, there is no need to deflate the Index of Industrial Production (IIP) for the possible inflation because it is an index, not the monetary value like GDP, which you will deflate for inflation by GDP deflator. You can seasonally adjust the IIP series and take the yearly growth rate (taking a 12-month difference) of the IIP series and use it for your analysis.