Question

Midday su can beseen overhead in chennia twise a year but not even once in delhi

Answer 1

this because of distance of delhi from equator is far as compared to chennai

Answer 2

The answer for your question is Chennai is closer to equator.

One can find the Sun aligns directly overhead to Chennai twice in a year but not a single time over Delhi. The reason behind this phenomenon is that the Chennai is located closer to the imaginary mid-line which we call equator.  Apart from the above reason, the whole of South India falls under the Tropic of cancer which had moved the part to a tropical climate zone. There is a phenomenon that sun can be found directly overhead to the regions that falls under the 23.5°N and 23.5°S at least twice in a year. Chennai falls under the latitude of 13.5°N.