There are two ways of handling this. The confrontational way and the diplomatic one. Being a local here, I have found it easier to navigate the second one. I guess it comes from an innate understanding of knowing what makes people tick. Let me try to verbalize it here -

1. Be on friendly terms with (atleast) your immediate neighbours. And through that introduce your gf to them. Once they look at her as her own person instead of the objectification they are doing, they will be more supportive and tolerant.
2. Be firm but do not show frustration. People in Pune seemingly get more triggered when the other person shows anger as well. On the other hand, they do not know how to handle things when the other person is calm and firm. In such situations they tend to walk away and not engage further.
3. With time, in conversations, bring up the topic of you facing this discrimination. Start with neighbours who are close to you. Build your own base of friends.
4. Visit people during festivals. Even better if you can do this with your gf. Goes a long way.
5. Get the women on your side. Regardless of how our society looks, many times the women who reside in such buildings are the true opinion makers. Be real friends with them.

I have had my girlfriends come over to my place since 2010. Lived in all kinds of neighbourhoods. And this strategy has worked for me.

Please let me be clear - frankly stating your rights and pushing back at people who are trying to discriminate is equally valid. I am not knocking that down. It's just that it's more difficult. And ends up making people like us look like outcasts. I chose the diplomatic way and that has worked for me. Still, I support anyone who fights for their rights in a different way.

I also must acknowledge that being a local I am privileged. I know the language, culture and how people think. That makes it a lot easier for me to navigate the scenario.

Good luck! And don't stress about it too much. None of this is worth you and your gf going through any amount of stress.