Is it an Indian custom to lay sheets on the floor when there's a gathering?

What kind of Indian? Do you mean from India??

Yes.

In such a gathering the floor is also the sofa.
Even though everyone will be leaving their shoes at the door, so the floor will be relatively clean, it’s a nicety to give the guests something to sit on that is cleaner.
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Yes, it is a common practice to spread a matress and make people sit on it. It is usually a traditional reed/cane matress (similar to the Japanese Tatami). It could also be a blanket (of any color, not necessarily white), if they run out of matresses. Here in India, it is not considered rude to be told to sit on the floor..it is the norm…of course, the houses will have sofas, chairs and all other modern things and people do sit on them but no one will find it odd to see a matress on the floor and they won’t hesitate to plonk on it if needed. The matress is not for protecting the floor…it is aimed to make guests feel at home….coz they guests usually lounge on similar matresses in their own houses….RIght now, I am sitting in my house, on a matress, legs folded, while typing this answer. I have a table and chair right next to me that I can use….but I prefer sitting down on the floor….most Indians are like me…

@AK, Ok, thanks. What about the white sheets, though? Is that just for when there’s a large crowd?

Let’s say there’s a prayer event or a musical performance. Would there normally be white sheets spread out on the floors in the main rooms?

@kneesox Nothing specific with white. Like I said, it could be of any color. Did you happen to visit an Indian house that had white sheets spread on the floor? Maybe they only had that color…I don’t know…but there is no specific tradition with ‘white blankets’. Usually people don’t use white blankets, white is not the color that you want on the floor, as it can show that it is getting dirty….but if there are many people in the house and that is the only colored blanket I have….I’ll spread it….:)

@AK, yes, I did. It happened to be a Hindu family. There were white sheets on the floors, like cotton bedsheets, not blankets or mats or mattresses. Maybe they were just large pieces of white cotton fabric, not necessarily sheets per se.

Also I recently saw a photo of a religious event in a Sikh home in the U.S. where it looked like people were sitting on white sheets on the floor. That’s what reminded me.

@canidmajor Point noted.

@kneesox Ah, I see. Yes, they could have used bedsheets. Was this Hindu house in the US too? Maybe they didn’t have the traditional mattresses. Usually, the mattresses are specially made for floor. Google for Jambukana/jambukanam/jammakalam. You’ll see that they have distinct patterns – long striped and darkish colored. Beautifully woven. They are not as thick as carpets or as thin as bedsheets. They’re sturdy. That is what we use if we don’t have enough cane matresses (tatamis).

@AK Even though I was born Hindu, I did not know all that. Thanks.

@AK, yes, it was, and in an area with a large population of Indian families, many of them first- and second- generation. The sheets were plain white, no pattern. Physically I had the impression that there was conventional Amercan carpeting underneath. There was also typical household furniture, sofas, tables, etc., pulled back against the walls.

Same thing in the news photo of the Sikh home I saw recently.

Thanks for sharing your knowledge.

I wonder if this is the photo you were thinking of.

@kneesox You are welcome. The color white symbolizes ‘peace’ (not in modern India, I should say….but traditionally it is…) You might find it strange but during bereavements, people wear white clothes here (which is the exact opposite of what it is there, I suppose). The symbolism is – let there be peace for the departed soul, in his new place. The photo shared by @Jeruba is that of a bereavement ceremony. So, I’m not surprised to see a white sheet there.