The average computer science professor salary in India is ₹ 660,000 per year or ₹ 264 per hour. Entry-level positions start at ₹ 462,500 per year, while most experienced workers make up to ₹ 1,560,000 per year.
First of all, you assume that after finishing a PhD, your chances for a professor position are good. As far as I can say (a CS post-doc@EU university), this is generally not straightforward unless you deliver a star PhD. Otherwise, expect at least one post-doc appointment. After a return from industry, unless you were very active in the research community during your time with a company, again post-doc is what you should expect.
Now to the answers, a European perspective. Generally in the EU, probably except for the UK, the academic salaries are governed by tables subject to annual change. In many countries these would be fixed without a variable component based on performance.
The positions of research assistants underlie TVoeD regulation (BAT in the past). There is no special category for a post-doc, all research assistants are treated equally. The salary scale reflects the individual's experience, that is, officially years of employment. Generally that should include also academic experience abroad too. Find the current tables also here - note the scales differ for West Germany, East Germany, Berlin and Hessen. You are interested in the class E13.
Professorships are remunerated according to the W scale. Again the salary differs from state to state, but according to this, we speak a baseline of about EUR 47k, EUR 53k and EUR 65k a year for W1, W2 and W3 professorship positions. W1 is for a Juniorprofessor, roughly equivalent to an assistant professor. W2 and W3 are two different levels of full professorship, the particular difference is mainly an experience/salary issue. The salaries are again graded in steps according to the number of years of experience at the particular position. You start at 0 and from there your grades increase.
Note however, at least in CS and generally in STEM, Germany does not fare very well in terms of foreigners on senior academic positions. It's relatively rare to encounter a non-German (or Swiss/Austrian) holding a professorship at a German public university.
The system is slightly simpler than in Germany, the salaries are fixed according to CAO (Collective Labour Agreement) regulation and subject to annual/bi-annual negotiation and modification. You can find the information on CAO here. Salary-wise you are interested in the salary table, columns H1 and H2 (Professor 1 and Professor 2). These are full professorships. Here we speak about EUR 65k and EUR 58k respectively as a baseline from which the annual grading increase starts. For a assistant professor, the columns of interest are 11-13, so the variance is big. E.g., 11 is also for post-docs, though sometimes assistant professors get that as well. Depends on the particular position.
Now considering positions in the Netherlands taken by foreigners, you are eligible for a so called 30% rule which basically states that you do not have to pay taxes for 30% of your income. That leads to a significant salary increase for foreigners in the first years of their employment in the Netherlands so even the assistant professor salary grades might not look extremely interesting, considering the 30% rule, they turn out to be fine.
All the quotes should be understood brutto before taxation and social system/healthcare/++ deductions.