I don't think you are getting the point of the Mumbai-Ganzhou distinction.
Mumbai is a Tier I city, hence electricity costs are expected to be higher than in Ganzhou. Nevertheless, as seen from the compilation of tariffs, if electricity for residents is $0.10 per KWH in Ganzhou flat; and $0.06 per KWH for 100 KWH and $0.11 per KWH for 101-300 KWH, then electricity costs in Mumbai are actually cheaper in the 100 KWH bracket and comparable in the 101-300 KWH bracket, within which most household consumption lies, with Ganzhou.
Also, electricity costs in Pune, which is comparable size-of-city wise to Ganzhou, is cheaper than in Ganzhou. Now, Pune is not a manufacturing hub, it simply has a larger manufacturing footprint than Mumbai. SEZ's and true manufacturing hubs in most states have subsidized electricity.
An important point to remember about some of the better private schools in India is that they are often owned and run by large trusts: the SVKM Int'l trust, for example, that runs the prestigious Jamnabai Narsee and Gujarati-medium Utpal Sanghvi schools in Mumbai, also runs several degree law, engineering, hotel management, commerce, technology and polytechnic universities not only in the country, but also abroad, apart from several other schools and pre-primary nurseries.