There’s different schools: private, public, home schooling, religious etc. I went to a public school, mostly with kids from not so great socio economic backgrounds. I wasn’t “don’t have anything to eat” poor, but I was definitely “can only afford 2 pairs of new clothes every year” poor. Most other kids were in the same boat.
The thing with schools in India though is, regardless of your status as a school, your curriculum is decided by one of the central authorities, either at a national level or at state level, and since the standardized tests for college admissions are the same for everyone, the variations in curriculum among these different schools are small.
Kids would repeat grades or have remedial classes for doing poorly. And the answer was to not lower the bar for everyone, but make students work harder for doing bad.