In Chinese culture, red is a lucky colour; it’s often used for gift giving or weddings. Similarly in Hinduism, red is considered lucky (as far as I’ve read) and brides wear red at their weddings. The only commonality I can see between Indian culture and Chinese culture (in terms of beliefs) is Buddhism, is it because of this or something entirely different or a coincidence?
Source: Barns were painted red for the reason of cost savings/ease of production. But that might fall into a rusty/muddy hue and not a vibrant red like you’re referring to.
It is a rust hue, because the iron used in its production is what makes it cheap
Also, red usually faded to a clay-ish brown. (Which is why the British used it for their marines…)