In the tech industry, when a full-time employee engages in for-profit work (which requires paying income tax), it is called moonlighting. We are neither lawyers nor rule makers. Our opinion in this article is completely for your legal defence. If your company (and HR) do not allow moonlighting, you can not do extra for-profit work.
What is About Blogging?
That depends on what kind of blogging you are doing! If you are operating a not-for-profit blog, then it may not be moonlighting. You can happily write about the life of Lord Krishna or Jesus Christ or Allah without earning from ads. The question of violating agreements only appears when you offer a for-profit service.
Can you write a sysadmin blog and avoid being labelled for moonlighting? Yes. Simply, you can not use any ad to make money or sell links or accept sponsored posts. If you are operating a professional well earning blog, then you may be liable to pay GST/VAT and Income Tax.
The counter agreement can be, the constitution usually allows any citizen a right to make money. But, no employer needs logic to expel an employee and your opponent has the right as well.
So, We Can Not Do Blogging or Run an IT Consultancy?
Why not? You can not do a full-time job and do other work which needs to pay taxes. When your family members operate the thing and you clap, that is completely legal.
So, you can not operate a for-profit blog with your real name, your profile photo, or your credentials. If you use a fake name then Google may not rank well in SERP and sponsors not going to pay you a few hundred dollars. In any business, to save some tax, you have to divide the business among the family members. It is completely legal when properly arranged (a CA can help you to arrange this thing).
But None in My Family Can Operate a Computer Properly!
You are operating the business against the name of your family member. You need to hire freelancers or maybe some full-time employees to get the job done.
Can I Use Fake Email, Anonymous Emails Etc?
You may argue that you’ll use a VPN. If your employer involves police, they may pressurize you by booking under worse sections of law so that you can not easily get bail and they can interrogate you. Litigation with someone may not yield a funny result.
Are You Personally Against Moonlighting?
I do not do any permanent job. Excessive stress leads to diabetes and hypertension. Diabetes is a dangerous disease and treatment is very costly. In most countries, health insurance does not pay the cost of Lantus (long-acting Insulin) and Apidra (short-acting Insulin). Everything related to diabetes is super costly.
If you are my employee, I will allow you all activities when you are not my full-time employee (i.e. contractual employee). The agreement is between you and me. When the agreement is breached then the question of the tort act arises. On internet-based work from jobs, it is common to perform multiple works simply because none provides you with any advantage of a full-time job.
As for India, Section 60 of the Factories act 1948 prohibits the double employment of adult workers in factories. Apart from that, an opponent may fire any section they want.
What You Suggest?
Blogging is very difficult to work. Most successful bloggers do not have a full-time jobs but they have different types of businesses.
You can develop free software, or get involved in StackOverflow. Your lawyer can defend your these actions. Always have a reliable, knowledgeable lawyer beside you.