Situation in Sri Lanka and India:     This can be explained taking  examples of several countries belonging to different geographical regions in  the world. First and foremost the overall size of the population in Sri Lanka  in particular and the geographical size of our island nation in general play a  big role in deciding it. Take for example our giant neighbor India, home to the  second largest Muslim population in the world after Indonesia. The number of  children in an average Muslim family in India is around 05 while in Sri Lanka  it is around 10 to 12 in the East and 06 or 07 in other parts of the country.  Given the sheer size of non-Muslim populations of India with equally the  geographical size of it, the family size of the Muslims in India and their  growth rate hardly make any adverse effect on other communities. However, when  it comes to Sri Lanka the present growth rate of Muslims make a horrible impact  given the non-Muslim families' average number of children hardly pass the  number 02. And also the sheer geographical size of India hardly make any  negative effect while in Sri Lanka it bears terrible consequences with non-Muslims  being evicted in their traditional places of   habitations giving way to the disproportionately large exclusive Muslim  enclaves as result of Muslim expansionism. 
    Tension among the communities has  already become a reality in Sri Lanka with the land greedy Muslim community  acquiring lands at an amazing rate resulting in other communities becoming  almost refugees. This has become a common phenomenon in the North- East region  as well which was under war for 30 years. With the conclusion of war Muslims  have been settling in in the former war zones at such a rate that there have  been frequent agitations by Tamils who were the owners of those lands before  the war. The latter community claims that the lands owned by them are  frequently seized to settle Muslims. This has been rampantly happening with a  Muslim Government Minster has been totally biased towards the Muslims when  settling them. There has been a simmering row going on in Mullaiveli in  Mulaitivu District which I highlighted in one of my posts too. So it is plainly  clear that the demographical changes that are taking placing in Sri Lanka due  to Muslim population explosion have a terrible bearing on other communities. 
    How other countries like Singapore, Japan and Australia cope up with the  problem:   
    The countries which have the  potential to face similar consequences like Sri Lanka have taken timely actions  to prevent it from happening. A case in point is Singapore which took actions  to impose a law prohibiting Muslim families not to raise more than two children  going in line as same as families of other communities. Singapore would have  been facing disastrous consequences given the small size in its population and  the land mass in a few years, had not such a law been imposed. Had this law not  been effective, the ethnic composition of Singapore which comprises Chinese and  Tamils as the first and second largest communities would have had a completely different outlook with  Muslims becoming the majority community in a few years. 
Take another example of  Japan which never gives citizenship to Muslims immigrating to Japan from other  countries. Given the small geographical size of Japan and the very slow birth  rate among Japanese population, the island nation would have become a sitting  duck to prey to the huge Muslim population explosion that would have been  unleashed by the Muslim immigrants as they have exactly done in many European  countries. 
Learning lessons from other countries Australian government has been  quite strict in its immigration laws when it comes to Muslim immigrants having  known well in advance the terrible consequences that Australian society would  have had to face when the population explosion is unleashed by the Muslim immigrants.  (Australians can't take chances given its small population size which is  similar to Sri Lanka's and very law growth rate). Australia has resorted to  take such sever actions despite the fact that the country is blessed with a  massive land mass and being a continent. What would have obviously made Australian  government to have been cautious was not to disturb the ethnic composition in the  country despite the fact the availability of lands has never been a problem to  them.                                
    Terrible consequences  that European countries are currently facing:   
    Most of the European countries  such as Netherlands, France, the UK, Norway, Belgium and numerous other  Scandinavian countries which were lax in their immigration policies towards  Muslim immigrants   are now reeling with  the terrible consequences of Muslim expansionism and Fundamentalism. Muslim  immigrants from Asian and African countries have unleashed such a huge  population explosion that the original European inhabitants face the danger of  becoming minority communities giving way to Muslims in a few decades. The very  low population growth rate among their populations similar to non-Muslim  ethnicities in Sri Lanka has led to the emergence of numerous far right  movements in Europe solely campaigning against Muslim expansionism and  Fundamentalism. So the situation that Sri Lanka faces now is similar to a  certain extent what some European countries face now. 
    Vulnerability faced by Sri Lanka 
Sri Lanka's unique situation in  demographically as well as in geographical size makes it vulnerable to face a  serious imbalance in ethnic composition in a few years' time if Muslim  expansionism in Sri Lanka is not checked.  By encouraging non- Muslim communities to  increase the number of children in their families will aggravate problems as  the Sri Lanka's land availability has been fast depleting even to accommodate  present population.               
    PS: The fact that Kaththankudi in  Batticaloa District has been identified as having the largest population  density per square Kilometer in the entire world underscores the terrible  situation that Sri Lanka is in. (Population in Kaththankudi is 100% Muslims and  this figure was first reported a few decades ago).