It was so devastating that many towns had no one left to mourn the dead. It hit hardest in the state of Gugarat, a prosperous, middle-class region where some of India's busiest seaports are located. Many of these ports were crippled or totally shut down, making any kind of aid nearly impossible. Thousands died and, because Hindu tradition demands cremation, funeral pyres and the smell of burning flesh penetrating Gugarat. First is the simple matter of infrastructure.
Poor areas suffer more from earthquakes than do wealthy ones.
Obviously, adobe shacks collapse more easily than do structures built with steel and concrete. Also, population density is normally higher in poorer areas and thus larger numbers are affected. That is why building codes, inspectors, evacuation plans, first aid courses, etc. are so crucial to forward thinking. Well over half of the world's population lives with none of this foresight so normal to most of us in the West. Another important factor is absence of governmental ethics.