Patent Law in India

The 2005 Amendments to the Indian Patent Act expanded the scope of patentability by (among other provisions) allowing patenting of new substances brought about by incremental innovations. What exactly is an 舖incremental innovation舗? And how does the amended Act alter the legal definition of patentable subject matter and restructure the essential criteria - utility, novelty, no prior publication, and non-obviousness - around which patent law revolves?