PSUs in India, for long, have had troubles conducting their recruitment processes with more than 100,000 students giving the exams for less than 1000 jobs (A selection rate of less than 1%). After sensing the exponential rise in the number of engineering students in India who wish to “land” a PSU job, the PSUs have decided that GATE score shall be the primary criteria for initial shortlisting. This change was the primary cause for the rapid increase in applicants for GATE 2012.
IOCL was the first PSU which successfully tested out this system and was followed, two years later by NTPC, IOCL & Powergrid.
Usually these companies release their recruitment notifications right after GATE notification, indicating that candidates have to take GATE to be considered for a job in their organizations.