Pakistan and Bangladesh are Islamist nations which both of them share the same belief. They both were separated from India in the very fierce religious wars and discrimination. Pakistan is located in the west of India which share the long disputed borders and military stand off. Pakistan which has the very close relationship with Beijing possesses the very destructive nuclear and warships. Beijing considered Pakistan as the most honest friend in which both of them share the common enemy, India. Bangladesh is not as powerful as Pakistan in military, but both of them have the very crowded populations and under Chinese influence.
In order to gain respect and counter-the stronger country, the small nations must join together to counterweight. there are many possible reasons that Pakistan and Bangladesh can be good friends to counter-India. First of all, Pakistan and Bangladesh as mentioned are under Chinese influence. Second of all, both of them share the same religious belief which has India as the enemy. Third, they need to join the be respected by India.
If Pakistan and Bangladesh will be good friends, India will face many challenges. First, these two countries and China will India in the very dangerous geo-politics. Second, the North East states of India will also seek for the independence. Third, China will use these nations as well as the string of pearls to curb Indian influence and threats. Fourth, these nations will never respect or afraid of India. If these things happen, it will be the declination of Great Giant India.