Complex sentence: Over the years, the houses have increased in height and density, and have seen more and more students renting rooms from the nearby universities, or preparing for entrance examinations of engineering, medical and civil services exams.
Split into simpler sentences: Over the years, the houses have increased in height and density, and have seen more and more students renting rooms. They are either studying in the nearby universities, or preparing for entrance examinations of engineering, medical or civil services exams.