Comprehension means a lot of things to a lot of people. Generally it means to understand, and reading comprehension means to understand written text.
Written text can be fiction but most of it is factual, such as 'India’s capital is New-Delhi' or 'the height of Mount Everest is 29,029 feet above sea level.' Generally, factual information given in a text is easy to understand. The reason why it is easy to understand is simply because it is a fact. Would there be any doubts as to whether New-Delhi is the capital of India or not? In our daily lives we are confronted with facts and, if we want to make our lives as easy as possible, it is important that we can understand the facts that are written.
If you were to travel to another city and you were using the train, bus or plane to travel, then you would need factual information on the time-tables of the services so that you could make your decision to travel at what time, in what class and so on. You may ask what if I travel by my own car? Then, too, you would need factual information on the best road to take, how much distance to travel, how much time it would take and so on. Such information could be provided by a road map or atlas and it would contain the factual information but you would need to comprehend what is given in the map or atlas.
Another facet of factual text is that you can draw inferences from facts given in the text which are also factual. If you watch the news on TV or read a newspaper you are faced with factual information. Even the information given to you by your teacher is factual information and you cannot afford to make mistakes in understanding it.
Read the text describing a sports event that follows and see how many of the facts you can recall correctly in the quiz afterwards.