Was it a Mir store? Or is it People’s Publication office/bookstore? The book store/publishing house run by ICP? They are still around. They used to stock Progress Publication books too - USSR’s literary cousin of Mir (they’ve stopped stocking Mir now). I am not from Delhi but whenever I’d visit I’d go there to check out some translations, especially Hindi translations of Russian works. I still go - I was introduced to Russian literature in Hindi and I still crave for that. I bought Cossacks’s Hindi translation few months back.

PS. I bought my first IE Irodov in Delhi though. Sunday market.