> China today is so different from India today? In terms of cleanliness
Urban Goverment in China versus India is VERY different.
In China, cities are given significant autonomy and a bigger pot of cash compared to prefecture they are in. Furthermore, the Chinese cities that most foreigners visit (Beijing, Shanghai) are under direct control of the Central Government.
In India, urban government is subservient to state government - with zoning, planning, and budgets coming from the state bureaucracy, especially in cities that HNers tend to visit in India (Bangalore, Gurgaon, Hyderabad). Let's use Bangalore as an example. Bangalore is India's tech hub and the economic engine for Karnataka, but urban Bangalore only has around 20 seats in Karnataka's Legislative Assembly out of 224 total. This means that state governments have little to no incentive to care about providing urban services and goods, when they can better invest in other constituencies that actually can flip the tide in elections.
The other aspect is that slums residents can swing elections, so any attempt to demolish a slum can destroy the incumbent party's shot at local elections. Slums/encroached land have significantly monetary value - the first generation who lived in a slum and built the residence often tend to move out and rent out the original building to a new resident while also having the option to mortgage the building to a local lender. If you are an unskilled migrant laborer, you are making around $100-150/mo in Urban India, but if you have a slum residence, if litigation happens for redevelopment, you might end up with around $10-20k and a free apartment (which you can rent out). The same thing happened in China all the time until the mid-2010s, and it's just the general cycle of urbanization.
That said, Indian cities are getting better and cleaner, but funding for urban infrastructure only really began in the last 2-3 years. Indian cities today aren't that much different than their Chinese peers in the 2000s, and the exact same kinds of problems (toxic smog in Delhi like in Beijing in the 2000s) but also development are happening (the Delhi redevelopment for G20 similar to Beijing's redevelopment for the 2008 Olympics).
Also, one thing I noticed is the 2nd most populous of each state tends to be much cleaner than the 1st. So Mysore is miles cleaner than Bangalore, Coimbatore compared to Chennai, Panchkula to Gurgaon, and Pune to Mumbai, which I assume is because there are fewer outsiders, so the electoral impact is higher, as most migrants (both from the same state or outside) continue to use their home town/village as their primary constituency in order to continue to maintain rural/town landholdings.