Mangal (Kuja) Dosha
A chart is said to carry Mangal Dosha when Mars sits in the 1st, 2nd, 4th, 7th, 8th, or 12th house from the ascendant (some schools also count from the Moon). That is the whole technical definition.
The tradition's concern was practical, not moral. Mars in these houses can create friction in partnership — because Mars is the planet of edge and heat, and the houses listed are all partnership-adjacent. The recommendation was to marry someone with a compatible Mars pattern so both edges could burn together instead of against each other.
What Mangal Dosha is NOT: a curse, a marriage-blocker, a reason to postpone your life, or a condition that requires a ₹51,000 puja to “cancel.” Roughly half of birth charts are technically Mangal Dosha under the standard rule — that alone should tell you it isn't a rare affliction. Two “Manglik” people marrying is not a supernatural fix; it's a compatibility of temperament.
What actually helps: honest conversation with your partner about how you handle friction. Physical activity that lets Mars run — sport, discipline, hard work. And time, because Mars matures with maturity. Nothing you buy will do this for you.