"Even if rideshare companies are charging iPhone users more, it’s not going to impact most Indian citizens because feature phones and low-cost Android handsets dominate the local market." Moot point since "most Indian citizens" are not in the Target Group for Uber / rideshare companies. At most, their TG is the Top 10% - and everyone in that 140M segment of the population surely has smartphones including iPhones. JFYI, Apple iPhone is the largest selling smartphone brand in India by value. And, among Top 10%, which is the real relevant target audience in this context, Apple might have a sizeable market share even by volume (I'm guessing 20-25%). So the alleged discriminatory pricing is not all that insignificant a topic.
"Uber and Ola responded to the CCPA probe by denying they use differential pricing." Rideshare price depends on time and location. Even if the price readings on the two phones were taken at the exact same time, they can't have been taken at the exact same GPS coordinates.
"But that didn’t satisfy Joshi, who in an answer to a parliamentary question said the matter had been sent for further investigation." Until rideshare companies came along around 10-15 years ago, auto rickshaws and black-and-yellow taxis never collected nor remitted sales tax / service tax / GST to Government of India. Uber, Ola et al do. Accordingly, rideshare companies have provided an additional source of tax revenue for GoI. Safe to assume that the alleged discriminatory pricing will boost the topline of Uber / Ola and, accordingly, GST revenue of GoI. OTOH govt has duty to consumers, OTOrH govt has vested interest in higher revenue of Uber / Ola, it'd be interesting to watch how this inherent conflict of interest gets resolved.