गैस बंद की?

You use this when you are about to leave the house. You can also use it as a check-in with a roommate or spouse. The grammar is simple. गैस (Gas) is the object. बंद (band) means closed or off. की (ki) is the past tense of 'to do'. You do not even need to say 'you' (आपने or तुमने). The context makes it clear. It is often said with a slight tone of anxiety or a quick reminder.

Use it when you are locking the front door. Use it when you are sitting in a rickshaw and suddenly panic. It is perfect for texting a flatmate if you left early. You can even use it metaphorically. If someone is 'fuming' or 'heating up' in an argument, a witty friend might say it to tell them to cool down. In a professional setting, you might ask a colleague this if you share an office pantry.

Do not use this in a fancy restaurant to the waiter. They might think you are complaining about a leak! Avoid using it in very formal speeches unless it is a joke about domestic life. Do not use it if someone is talking about 'gas' in a medical sense. That would be a very awkward misunderstanding. It is strictly for the kitchen appliance.

In Indian households, the 'Gas' is almost a family member. Mothers are famous for asking this three times before every trip. It stems from the transition from wood fires to LPG cylinders in the mid-20th century. Safety awareness became a cultural meme. It represents the transition from 'leaving the hearth' to 'managing a modern home'. It is the quintessential 'Mom-ism'.

You might hear गैस बंद कर दी? which is slightly more complete. Some people say चूल्हा बंद किया? (chulha band kiya?) which means 'Did you turn off the stove?'. If you are being very polite to an elder, you say क्या आपने गैस बंद कर दी?. But in the heat of the moment, the three-word version is king. It is fast, efficient, and saves lives (and electricity bills).