I am a Prime Minister's Research Fellow (PMRF) at the Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur WB 721302 India. I work with Prof. Somnath Bharadwaj on Theoretical Cosmology, related to understanding various fundamental issues in structure formation and evolution of the first sources of light in the early universe. I simulate the evolution history of the universe to study the Epoch of Reionization and its statistical properties. I mainly use the 21-cm radiation originated from neutral hydrogen in its ground state via spin-flip transition, as a probe of this epoch.