In practice yes, but he does it legally. For example, he might say ‘in order for us to know you are an Indian citizen, you have to show us a birth certificate’. This sounds perfectly reasonable, but poor and less educated people are less likely to have a birth certificate, and also generally more likely to vote for opposition parties, so in practice it will preferentially exclude them. Now this is an extreme example and will get struck down by the courts, but there are all sorts of small ways in which he can make it slightly harder for certain sections of the population to vote.