Mangal Dosh
In Vedic astrology, Mars, Saturn, Rahu, Ketu, and the Sun are regarded as cruel planets. Among them, Mars is considered the most severe, especially if it is unfavorably positioned in a person's birth horoscope. When placed poorly, Mars can be particularly detrimental to married life.
When Mars is positioned in the first, second, fourth, seventh, eighth, or twelfth house in a Kundali, it creates Mangal Dosha. This condition should be examined not only in the Lagna chart but also in the Moon chart and Venus chart. A person is considered non-Manglik only if Mars does not afflict any of these three charts. Mangal Dosha is also known as Kuja Dosha and Bhauma Dosha. Individuals with Mangal Dosha are referred to as Manglik.
North Indian astrologers don't consider second house while evaluating Mangal Dosha while South Indian astrologers don't consider first house while evaluating Mangal Dosha in a birth horoscope. However, there is consensus that both houses should be considered while evaluating Mangal Dosha and Drik Panchang considers first as well as second house while evaluating Mangal Dosha.
Many Kundalis have Mangal Dosha but in most of them Dosha is cancelled due to various combinations of Mars and other planets including state and house position of Mars and other planets in the horoscope.
If Mangal Dosha is present then all combinations which nullify it should be looked into. There are many rules which cancel Mangal Dosha. Drik Panchang considers the most widely accepted rules which cancel Mangal Dosha.