Dear Ruban.
if you r a salryholder then uou can can claim for exccempyion in HRA recieved by from your employer with ref. of section 10 ( 13A) ..
1. 50 % of Actual HRA Recieved or 40 % in case of non metro cities.
2. Rent paid -10 % of Salary
3. Actual HRA Recieved.
Least of above shall be excempted from your actual HRA recieved.
HRA excemption is avialbale in only that condition when you are paying rent and you have to produce rent reciept to employer.
now, as you discussed that you have taken home loan and you house property is let out or not is not clear .. i suppose that is letout so rent recieved from letting of your property shall be considered as House property income and out of such income you can claim diduction of section 24 (B) upto 150,000 for prior acqusition of house property .after all of that you have taxable income from H.P
now, your third question is Diduction of EMI for house loan .. ya sure you can claim diduction u/s -80 C for only principal amount paid against loan ,, Whole EMI of a year will not be allowed as diduction (less actual interest )
i hope you queries might be clear.
Regards,.
Narendra Kumar