Hi

you can go to this website, 

Earthexplorer.usgs.gov, and search your region, then you can download Dem of region,

Good luck!

Dear Dagani, 

you can access one of the following websites: 

http://glcf.umd.edu/data/ 

OR 

http://reverb.echo.nasa.gov/reverb/

Good luck. 

Please check these links and pdf attachments.

http://www.omicsonline.org/open-access/assessing-hydrological-response-to-changing-climate-in-the-krishna-basin-of-india-2157-7617.1000211.php?aid=29430

http://india-wris.nrsc.gov.in/wrpinfo/index.php?title=Basins

Best of Luck

Dear Rao,

Please check these pdf attachments also.

Good Luck

Register here and download wherever  you want.

http://earthexplorer.usgs.gov/

you may consider using these products freely:

Hydro 1-km, SRTM 90m, STRM 30m, ASTER 30m

depends on the resolution you need

You can also register and download CartoDEM (30 m)  from NSRC/ISRO's BHUVAN portal.These are prepared from Cartosat images which have high resolution of  2.5 m

http://bhuvan.nrsc.gov.in/data/download/index.php

• NGRI Hyderabad did DEM in Musi and Krishna River Basin. 
• Kindly contact  Director, National Geophysical Research Institute, Hyderabad 

Dear Rao

you can download from the website

http://srtm.csi.cgiar.org/ 

SRTM, ASTER, .....U CAN GET IT FROM LANDSAT.....OR FROM Indian remote sensing agency(IRSA)... which have 4 band