Why is there a need for international banking regulation?

What will be an ideal response?

First, central banks are concerned that without an international regulatory framework to ensure that an adequate level of capital is maintained in the international banking system, bank failures could lead to a global financial crisis or at least domestic crises could spill over into other countries.
Second, the variety of different national regulations potentially gives an unfair advantage to banks from countries with laxer regulatory standards, and this could decrease the soundness and safety of the international banking system overall. International regulations can create a more level playing field that avoids potential under-regulation if individual regulators compete to see who can be the least strict.