Inflation is a period of accelerated expansion in the history of the universe in which the quantum seeds for the structures we see today in the universe are created. The data from the Planck mission strongly confirms it as the paradigm of structure formation. A plethora of models have tried to realize the idea of inflation. In some of these models, the scales are stretched to the extent that Planck scale might have become of the observable size, leading to the possibility that quantum gravity might be detectable. I will briefly review some of the models used to study the effect of Planck scale physics in the CMB and methods used in supergravity and string theory to build inflationary models, and elaborate on their observational signatures. Opponents of inflation have pointed out that the simplest models are excluded by Planck. I will discuss how one can possibly reconcile these kinds of models with the Planck data using new physics.
