Therefore it is clear from my question that it is a case of present unfulfilled wish instead of past. still some respected members chose the use of "took" (past tense) but you used "is taking" (present tense).
I want to ask humbly, which one is correct ?
One occasionally respected member suggested the subjunctive. It can't be the past tense (as further evidenced by ems's post). I think you have subjunctive in Hindi, so I guess you understand the concept. Your analysis is correct. It's an unfulfilled wish in the present, and hence we use the subjunctive mood of the present tense, ie. 'took'.
It can't be the past tense because the following is not grammatical: "If it were possible to go near when one of the volcanic
eruptions TOOK place (last week), we would see a grand sight."
Everyone seems to understand that 'were' is subjunctive in: "If I were you, I would be embarrassed". But some people miss it if the verb isn't 'were'. Eg. "If a volcanic eruption
took place, it would be awesome." I suppose that's because many lessons on the past subjunctive seem to use 'were' as the only example.
Ask yourself, if 1 is subjunctive, why are the rest past tense?:
1. If I were an astronaut, would you be impressed?
2. If I took your bicycle, would you be angry?
3. If an eruption took place, would you be surprised?
4. If it were possible to go near when one of the volcanic eruptions took place, we would see a grand sight.
http://www.grammaring.com/past-subjunctive
... and others