Why is Indian manufacturing so behind compared to China ?

Autocracy vs democracy. China got to manipulate its currency for two decades at a stretch - got it pegged at 6 remnibi to usd keeping exports cheap, influenced/lobbies/spied at the highest levels in the US government for decades (look up Larry Wu Tai). This meant unbelievably high USD inflow into China for decades. Chinese nationals who emigrate to US are loyal to China, steal IPs, some are even PLA trained - look up PLA members posing as students in ivy leagues. China pays up American profs to work for them (look up collaborations of Wuhan institute of virology). Their communist background helped since most American institutions are infiltrated by communists thanks to Russia paving the way - so much that they got US to dethrone ROC (Taiwan) from UNSC. Till today, US does not recognise Taiwan as an independent nation despite the grandstanding. Not saying this is all wrong, but they played geopolitics very well over decades and got loyal, nationalistic citizens.

Manufacturing needs better connectivity infra, very reliable electricity and water supply, less bureaucracy, easy tax rules and cheap but skilled Labour.

Let me take China: the cost to transport something from the deepest inland factory in China to a port in US is cheaper than to transport the same between two states in India. Chinese goods are cheaper in US then even from Mexico due to the most smooth roads, rail and shipping ports. India's roads are not as super, we even had customs intra state before GST.

Until this is solved, all other factors are moot, so let's not even get to them.

China had Deng Zioping, the visionary leader...

India had Indira Gandhi in whose regime, taxation rate was 97.5% for rich ... Our "socialist"politicians like Lalu and Nitish still don't want to be photographed with any industrialist because it will harm their "Socialist" image ... Bihar be damned

Lazy workforce and half knowledge talent who always look at jugaad attitude.

Just see businesses , I was talking to SMB cusotmer I will employee a guy for 10k with excel knowledge. I don't need software.

Because, if we open manufacturing say for eg. In Karnataka, the state govt will demand that 80% of all those jobs goto Kannadigas, then the local kannadiga population will threaten, bully, beat outsiders for coming to their "beautiful" cities. Then the factory owner will have to employ these same illiterate useless kannadigas.

But the kannadigas know they didn't deserve it and were able to bully, best threaten their way into their jobs, so they have no need or desire to work hard or maintain standards. Result? Inferior products being created

Replace this with any state, we are all protectionist, countries within a country, feudal medeival minded subservient people. Not just to foreigners, but rather any godman/fancy dress champion and we will continue on this path forever.

It's all in education. In Chinese society all types of engineering are appreciated equally, taught equally. In India, everything evolves around software only. This is the 90% reason for this failure. All other analysis can fall under the remaining 10%

One word: Dictatorship.

A lot of factors, but primarily this.

We are not behind in capabilities, we are behind in adoption

A few things -

1. Lack of focus on education after independence. Policymakers discounted the need for education amongst the masses, mostly for communities working as daily laborers. E.g., China has 10+ universities that are present in the top 100 global universities and India has none.
2. License Raj until the 1990s. India was late in implementing liberalization and opening its economy to the world.
3. Poor tariffs for imports/ trade policies. As an example, tariffs were still hurting the electronics industry in India until a few days back when the govt. decided to slash the tariffs on electronic component imports
4. Though democracy cannot be discounted for a country like India, it may be possible that democracy has slowed the pace of aspects like land acquisitions required to promote growth
5. Centralization of power led to a lack of incentives for the local governments to identify and promote the strengths and competition.

Having sourced from China for a long time I know first hand that it is not one factor it is a whole lot of stuff that China cleverly put together to create a perfect storm. I remember Narasimha Rao as PM saying in Davos then that India has equal capability but we will grow with social justice only and respect labour laws. But the contrary part to this social laws bit is that commies of Russia and China works hard in India thru trade unions to disrupt factories. Even today the apple factory in chennai faced a one day tools down for higher wages. In China that will never happen. China in short subsidised input costs as well as managed exchange rates and created great great infrastructure to enable manufacturing. But while travelling to far east it must also be said that eastern people are far more productive per hour of work. They are diligent and focussed and follow instructions to the T. Even in 1990 Thailand had higher min wages by 2x of India but 4x productivity in sea food factories. Also Chinese creativity is marvellous. Basically we Indians are good at soft skills and Chinese at hard skills.