That is personal anual income and not family income I suppose. Remember that India has around 30% of people far too young to use cellphones. A family might have one phone and will happily spend $28 per year for the $30GB data per quarter. Also it is mostly prepaid with hundreds of plans to chose from so people chose based on their needs.
Smartphones are extremely important part of India's way of life as almost everything else is regulated to death. It is a ray of light for most poor people and you will find people who might not have a toilet but will own an android smartphone.
[0] https://data.worldbank.org/indicator/NY.GNP.PCAP.CD?location...