Income from House Property

1. As per sec 24(b) interest on borrowed capital will be allowed as deductions to the extent of interest paid or Rs. 200,000 whichever is lower. 
2. Insertion of the new condition has made a huge difference in many scenarios with respect to claim of interest on borrowed capital as a deduction. An assessee who paid the interest shall produce a certificate to this effect in order to claim deductions under this section. 
3. So from the above reading, it can be seen that only if the interest is actually paid or payable by the assessee the same can be claimed u/s 24(b). 
4. In your case, the loan was obtained by Mr. A and interest is paid by Mr.A alone. So deductions cannot be claimed by Mrs.B even she is being a Co-owner of the property. 
5. The other aspect is claiming of interest amount. Whether Rs. 2,00,000 or Rs. 1,00,000 ..? 
Income tax is specific to each assessee and it sees every assessee separately and it cannot be viewed from other person income except in certain situations. Hence if the assessee pays interest on borrowed capital specified u/s 24(b), he can claim the full amount as deductions subject to the maximum of Rs. 2,00,000. Since his co-owners share of income is getting taxed as per his slab rate.  
6. Mr. A can claim the full amount as a deduction of Rs. 200,000 u/s 24(b) provided he obtains a certificate to this effect from the borrower.  
Please correct me if the above interpretation has an alternative view.