Varun Mehta

You will have to take an exam, which has 125 Multiple Choice Questions. Thats it, if you pass that, you are a CEH.

But just like doing B.Tech does not make you an Engineer if you are not good at it, Similarly, doing a course just for the sake of certificate wont actually make you a 'hacker'.  The Cyber Security is a perofrmance based field. 

Now your second question, where and what to study.

Most of the hackers out there are actually self taught. There are multiple resources available online today but they are unorganised and mostly not just comprehensive enough. Plus self learning takes time and effort, and you have to always stay updated.

To meet the challenges faced by green hats, our industry leading team came up with a program that focuses on hands on practice, in depth knowledge and adaptable expertise rather than on doing away with a certificate. 

Remember, its not about entitlement. Its about the quality of journey.

No Bharath, you won't find any 'grey hat' training institutes out there, atleast not via official channels. But the truth is, every white hat if not still, atleast was, once a grey hat. One of the closest entity to the grey hat courses is our extended cyber security program, which lets you get your hands dirty in real world live projects. 

When I was a beginner, I tried many in Delhi, which I wont name now. But trust me, moat of them are there to make revenues. They teach you some outdated tools, give you a worthless certificate, and charge you in thousands. The best is to learn by yourself as much as you can because spoon feeding is not the fortey of this field. For any other assistance, I am there..:)

Which knowledge domain is more important in ethical hacking, web development (PHP, HTML) or network knowledge (CCNA)? Is there any other as well?

Ethical hacking is an umbrella term, and there are multiple sub domains wrapped in it, each having distinctive importance. If you want to go in web-app hacking, its great to have basic knowledge of php, html etc, on the other hand, for network hacking, u must have in deapth knowledge of networks, ccna is just a certification though, what u 'know' defines ur intensity. Having said that, its always good to focus on one sub domain in deapth rather than going broad and trying every other aspect of ethical hacking. Good luck!