That means, you cannot make more than that amount a year.
This is a three bedroom apartment and it's approximately 650 sq, ft according to the description.
You should know that HDFC also means, it has to be your primary residence, and you cannot rent it out.
In general there is a flip tax of 30% of the profit to be paid to the reserve funds when you sell the unit. There are many different forms of flip tax though, some HDFC have a so called 60/40 rule which means 40% of the profit goes back to the city when you sell it.
HDFC are great for people with a more modest income, it is a very good program but it is important to be well advised on this kind of properties.