Hi Rashmi
Ur question has a 100 page answer, lots of Call Centers are doing very well in India and as per the current studies, overseas markets outsourcing their call center needs to overcome their huge spendinga without compramising on quality.
Many CALL centers are in infancy stage due to improper training facilities and technology selection.
Delhi, Noida ,Banglore, Mumbai and hyderabad are the major tier cities offering CALL CENTER SERVICES and catering to fortune 500 companies including GE.