Complex sentence: Because of lesser career opportunity in village, people are slowly migrating from to metropolitan cities like Delhi, Kolkata, Bombay and likewise in search of better means of livelihood which accounts for the decline in village population in recent years.
Split into simpler sentences: Because of lesser career opportunity in village, slowly people are migrating from this village to metropolitan cities like Delhi, Kolkata, Bombay in search of better means of livelihood. It accounts for the decline in village population in recent years.