Explanations:
To understand which is the largest South Indian city, we need to consider both the population and the area of the cities in question. The term "largest" can refer to either the population or the geographical area, but in this context, it generally refers to the population.
Bengaluru, also known as Bangalore, is the largest city in South India in terms of population. It is the capital of the state of Karnataka and is a major economic and technological hub. The city has a population of over 12 million people, making it the third most populous city in India. It is also the largest city in South India in terms of area, covering approximately 741 square kilometers.
Visakhapatnam (Visag), located in Andhra Pradesh, is a significant city but has a smaller population compared to Bengaluru. It is known for its port and industrial activities but does not surpass Bengaluru in terms of population or area.
Hyderabad, the capital of Telangana, is a large city with a significant population, but it is not in South India as defined by the states of Karnataka, Andhra Pradesh, Tamil Nadu, and Kerala. It is located in the northern part of the Deccan Plateau and is considered a part of the South-Central region of India.
Chennai, the capital of Tamil Nadu, is a major city in South India with a large population. However, it is still smaller than Bengaluru in terms of both population and area.
Therefore, based on the population and area, Bengaluru is the largest South Indian city.