Why Indore is known as "Mini Mumbai"? Not a good Nickname tbh

Gwalior – The City of Music, Bhopal – The City of Lakes, Jabalpur – Sanskardhani, Ujjain – Avantika Nagari Every major city has something interesting behind its nickname, reflecting its history and identity. But what’s with Indore? Why is its nickname linked to Mumbai? "Heart of Malwa" would have been a better nickname for Indore.