The rioting in Mumbai by Shiv-sainiks is too common (a tactic) to be deliberated. Despite that, I opine that migration is too important a topic to be ignored. Being a Bangalorean, I take the Mumbai and Bangalore examples to put forth my submission.
This is not the first time migration has been raised in Mumbai. Shiv sena has been bringing this issue into national forefront for more than a decade now. The 'Mee Mumbaikar' campaign was more than successful on that aspect. I support the Sena on this issue, since I find their 'grievance' valid.
The Sainiks have been opposing the influx of Biharis and UPites to Mumbai. But the same sainiks have accepted to share space with Gujaratis. The sainiks are not hostile to the large populations of Goans and Managaloreans in Mumbai, nor to the much smaller south indian migrants. Similarly, in Bangalore, Andhraites are acceptable. Despite the Cauvery dispute, Bangaloreans are not hostile to Tamilians and Keralites. But the same Bangaloreans consider the 'northies' as migrants. Why so?
To the local people (of Bangalore, Mumbai or any other place), migrants are those who are not culturally similar to them. This is the reason that people from some part of the state moving to the larger cities within their state are not considered migrants by the local population, even though they are technically migrants. While Gujaratis, Goans and Mangaloreans have integrated with Mumbaikars, the Biharis live as a separate community. Similarly in Bangalore, the northies are those who live independent of the local mix of kannadigas, tamilians and teluguites.
In Bangalore, the VV puram area was traditionally habituated by the telugu-speaking Shettys. Shankarpuram had only Brahmins residing, Ulsoor probably has the highest percentage of tamilians outside Tamilnadu. Hardly anybody in Shivajinagar is a non-Muslim. Today the times have changed. VVpuram and Shankarpuram have more Marwaris/Jains than the local mixture combined. Infact, the Jain College has often been blamed for loss of moral values amongst south Bangalore youth, though the same is not said about the colleges run by other communities. A good indicator of this change is the places of worship that have sprung up in recent years. It is not for no reason that the majority population in Bangalore subscribe to these views (rather I subscribe to the majority opinion).
As long as theses communities are separated from the mainstream, they will continue face this opposition. Even though I 'migrated' to Singapore 6 months ago, have I made an attempt to join the local population? No, but for speaking in the local English accent, only to make fun. I understand that this adaptation is not easy, but is highly necessary.
Having said so, the 'migrant' communities have played a very important role in building their adopted homes. Some of the best Kannada litterateurs (DVG, Maasti and many more) were born non-Kannadigas. Some of the entrepreneurs who have built the country were migrants. They deserve a place in their adapted/adopted (if they adapt) home.
As far as Bangalore is concerned, language is the main barrier for the migrant northies to mingle with the majority population. I had a classmate during my engineering days, who was born and brought up in Bangalore, but could hardly speak or understand Kannada. It wouldn't have happened if he had played with the local kids as a child. Probably his parents were afraid of him mingling with the locals. Or probably the parents of locals did not trust him. This mutual mistrust still exists, probably to a larger extent.
To build this trust, schools can play a very useful role. They can put a little extra effort to make sure such kids learn the local language properly. They should be made to play games with the general population. Group assignments can be given to students, with groups consisting of diverse individuals. 'Unity in Diversity' should be inculcated in the children, not just taught/told to them. Such constant interaction in the formative years of the children will help such 'migrant' communities join mainstream.
Another important action is to curb migration। The main reasons for migration are better quality of life and better employment opportunities, to name a few. So the primary cause for migration is lack of inclusive development. If better education, jobs and social infrastructure (water, electricity, roads, police etc) can be provided in the less developed districts, the migration from those places will reduce. This will not only allow development of these regions, but will mean less 'friction' in the already 'cramped' cities of the country. I recently read that the NREGS (the UPA brainchild) implementation in Tamilnadu had reduced the migration from the particular region.
Hope these measures will help...