Here I was, thinking that you would provide an argument based on actual substance, but it's simply something petty.
Your point regarding hijab "fashion trends" is pretty stupid, because you can simply stick to only allowing a simple, single coloured, hijab of the schools choosing, which they all must wear. Issue solved.
As for "looking different" and "standing out", everyone is literally already wearing the same uniform from head to toe. That is enough to fulfil the purpose intended for a school uniform.
How does wearing a hijab prevent anyone from focusing on education?
And there is no social status difference, it is religious diversity, which is very much present and acknowledged in India.
The most prestigious universities in the world, the most professional and powerful militaries in the world, operate perfectly and professionally with no disruption, yet it seems to be a problem for a random school in India.
Given the common, and rising, Islamaphobic sentiments in India, as well as the poor arguments provided by you, I think it would be correct to assume here that this is just some good old fashioned Islamaphobia. Would not be the first time!