(1) We cannot compare Mumbai Locals with Delhi Metro as there is drastic difference between the quality of service. The former is basically an emu passenger train sharing infrastructure with long distance/ freight trains and are much more over crowded, smelly, hot and humid journey where as the later have a dedicated infrastructure with much more comfortable and air conditioned travel backed by a good announcement system. Mumbaikars are paying much higher fares for the Metro train between Andheri and Ghatkopar.
(2) After a decade long freeze on fares imposed by the past RMs, the second class fares have really gone too low (especially monthly passes) and need to be increased to a reasonable level so that financial viability of...
more... passenger operations are not totally off the track. Associations like Yatri Sanghs, Unions etc always demand for heaven, but IR need to act reasonably, especially in matter of fares.
(3) Delhi being national capital gets much higher allocations/ funding for infrastructure and much more importance than other comparable cities and a little bit of jealous feeling towards the pampered ones is natural.
(4) Mumbaikars are known to pay reasonably high for good services, unlike Kolkata where there is maximum resistance for a little increase in public transport fare. Their reputation as law abiding (Buying proper tickets and following rule of law/discipline) is better than most of the other metro citizens.