I am strongly agree with your question statement in now a days as follows:

"In Indian Universities necessary to change the requirements for studying MBA .,like 2 years Managerial experience in any organisations / Institutions / Colleges"

In any graduate program, experience matters but changing the student attitudes about how they seek a higher institution of learning will also play a significant role in the long-term development of internships and other programs.  First, I do not have an MBA but an MS in Operations Management and later a PhD.  Everything made more sense and allowed for iterative thinking because I had 20 years of diverse industry experience.  But it is also true that it is harder to get experience while attending the MBA program.  Hence, it is necessary for those seeking an MBA to perform due diligence in finding a program that would allow for internships and other access to experience during their education experience in the event that they cannot garner experience prior to applying for graduate studies. I attended Kettering University for my MS where they have a co-op work program in place for undergraduates.  It would be ideal for something like that to occur at the Master's level but would take a very long time to evolve.  Since many cannot wait for this change to occur, students must seek out those schools who can better prepare them for the working environment and that might mean leaving their first choice of schools for one that would offer them more access to experience in the form of co-ops, collaborative projects, internships, and other avenues for practical application.  When the education system begins to see the impact of students opting for schools with these programs, then they might realize the need as more students understand that in many big name schools they are not getting access to programs that they require.  There simply is not enough to go around.  

Lot of debate going on this hot topic, almost every where. Seminars, workshops, think-tank summits and even research-books [ like ‘Rethinking the MBA’, by Srikant M Dattar; http://www.hbs.edu/faculty/Pages/profile.aspx?facId=6443 ] making this ever a burning issue.

Still it remains in-conclusive: which is better.

One school prefers a mix lot (of freshers & those with some work-ex) and other do give emphasis on minimum requirement of prior experience (like ISB) and some needing Engineering pre-qualification (like the MBA's of IITs).

Some also try to make it effective 3-Sem (or one-&-half years show), with or with out one project learning in any company. Options are also their to have some job-like- experience, in the form of Summer internship (on-job-training). So, most of the MBA courses have direct or indirect industry linkage (whether prior requirement or done during the course itself).

When we consider the job-requirement in the market (and the options available with courses), I personally don not feel it to be good to make it compulsory (to have prior work-exp) for all the Institutes. Let there be flexibility.

The recent news making round is that top academic institutes of India (like IITs) are considering to reduce the duration.

it is also necessary to have rigorous study schedule which makes MBA effective