The churidar is the trouser worn under kurtas, sherwanis and bandhgalas, and it takes its name from how it behaves: cut longer than the leg so the extra length stacks at the ankle in folds like bangles, churi. It sits close through the seat, thigh and calf, much closer than any Western trouser, and narrows to the ankle. Getting that right needs either your exact measurements or a great deal of luck. A churidar cut for you at Sellers does what the garment is supposed to do, and it's the cheapest way to make an expensive sherwani look expensive.
What a well-fitted churidar looks like
It's smooth over the seat and thigh, with no horizontal drag lines and no vertical creasing. It narrows steadily from the thigh to a close fit at the knee, then tighter again to the ankle, where the surplus gathers in even, regular folds rather than one lumpy heap. The waist closes cleanly, usually on a drawstring through a casing, which has the useful property of still fitting you next year.
Ready-made churidars fail at every one of those points on most bodies. Seat-to-waist ratios vary hugely between men, thigh-to-calf ratios vary just as much, and leg length can't be averaged. What you get off a rail is usually too wide in the thigh, too short to stack properly at the ankle, or both at once. On this particular garment, cutting to measure isn't a luxury, it's the only route to the intended look.
Cloth and weight for a churidar, and why both matter
Churidars come in two cloth families: cotton and cotton blends for everyday and casual-formal wear, silk and silk blends for weddings and festivals. Weight matters as much as fibre. Too heavy and the cloth won't stack at the ankle, it will just bunch. Too light and the folds collapse and look thin.
For everyday use, a fine cotton or cotton-lycra in the 120 to 160 gsm range is the sweet spot: light enough to drape, firm enough to hold the gathering. You want some stretch too, because you'll be sitting, climbing stairs and getting in and out of cars all evening while the leg stays close.
For a festive or wedding churidar under a sherwani or bandhgala, a plain silk or silk blend in ivory, cream or black is the most useful thing to own. Silk lifts the whole outfit and falls cleanly from the hem of the coat down to the ankle, which is precisely where everyone's eye travels in the photographs.
Churidar or salwar: which one to wear
A salwar, the loose wide-cut alternative, is a completely different proposition. The churidar is close and precise; the salwar is generous and easy. The churidar belongs under fitted upper garments, sherwanis, bandhgalas, fitted kurtas, where a close leg completes the line and holds the whole outfit together. The salwar belongs with the Pathani suit or anywhere the point of the outfit is comfort and flow rather than shape.
For weddings and ceremonies the churidar is nearly always the better pairing, because a formal sherwani or bandhgala needs that clean lower line under it. For a long, hot or relaxed day, the salwar wins on comfort and nobody will think less of you for it.