Multi-zone emission modeling of blazar flare : PKL 1510-089 as as example

	Blazars are a special class of AGN, with relativistic jets pointing towards the observer's line of sight.  They emit in almost all wavelengths ranging from radio to very high energy gamma-ray.  The complex nature of multi-wavelength (MW) emission of blazars can be explained by studying the MW SED.  To model the MW SED, generally, people use the single zone emission model.  However, sometimes the single-zone emission model fails to explain the MW emission.  In this talk, I will discuss the conditions where the single emission zone is not suitable to describe the MW emission.  Further, I will discuss the particular case of PKS 1510-089, whre a two-zone emission model is required to explain the total SED.