The American style of presidency is a system of government in which the executive branch is headed by a president who serves as both head of state and head of government, and there is a separate legislature. This system is in contrast to the parliamentary system, in which the executive branch is headed by a prime minister who is typically chosen by the legislature. 

The disadvantages of having an American-style presidency in India are:

1) There is a risk of the president becoming a dictator

Under the American system, the president has immense power and authority. He can unilaterally take decisions without consulting the parliament or the people. This can lead to abuse of power and the rise of a dictator.

2) The president is not directly accountable to the people

The president is not elected by the people of India. He is elected by the members of the electoral college. This means that the president is not directly accountable to the people of India & to the legislature in the way that a prime minister is. This means that the president can take actions that the legislature may not agree with, and there is no easy way to remove the president from office if they do something that the legislature does not like. 

3) The president can act without the approval of the parliament

The president can take executive actions without the approval of the parliament. This can lead to a situation where the president is not accountable to the parliament.

4) The president can declare a state of emergency

The president can declare a state of emergency in the country. This can lead to the suspension of civil liberties and the curtailment of democracy.

5) The president is not responsible for the day-to-day working of the government

The president is not responsible for the day-to-day working of the government. He is only responsible for the formulation of policy. This can lead to a situation where the government is not run efficiently.

6) The president has more power than the prime minister. This can lead to a situation in which the president can abuse their power, and the legislature may not be able to do anything to stop them.