clarification regarding HRA on Temporary Duty

I am posted in chandigarh and has been sent on TD @ Delhi for 2 years. I have surrendered my accomodation in chandigarh and now having rented accomodation in Delhi . My HRA got deducted as they are saying you are not living in chandigarh, however my other colleague from other places like Dehradoon n pune are getting 30% HRA applicable to Delhi..
I want rule which clarifies the 30 % HRA so it may be forwarded to CDA...Please Help

Thanks & Regards

Ankur Trigunayak

trigunayak@gmail.com