Voting Rights for Indians Living Abroad

Since many of our readers are Indians living abroad I thought there would be interest in Abhinav Chandrachud's op-ed in today's Hindu, "Overseas Citizens: A Horse with No Name", in which he calls for giving voting rights to Indians residing in foreign countries. As he points out, government officers are entitled to vote while living abroad, but not those Indians who are otherwise working or studying outside India.

I noticed this election cycle there seems to be a new group of younger candidates that have spent time studying outside the country, returned and made a name for themselves, and are now running for political office. With so many talented Indians working and studying abroad right now giving them the right to vote may help entice them to stay politically active and think of themselves as invested in their country's future in a different way. This could pay large dividends down the road even if just on the margins.

Does anyone out there have a good understanding of the constitutionality of not allowing Indians living outside the country to vote, especially if government officials outside the country can vote? This is not my area, but I'd like to hear others who do know more speak to whether they think there is any sort of legal case here.