The Indian Scheme

In one line

India copied neither the American wall between the three organs nor the British habit of having no wall at all: it gave each organ a described job, joined the executive to the legislature on purpose, kept the judiciary apart, and armed each organ with a few weapons against the others.

In the wording a student can write in an exam: the Constitution does not enact the doctrine in its rigid form, but it does effect a clear demarcation of functions. In Rai Sahib Ram Jawaya Kapur v. State of Punjab the Court held that it "has not indeed recognised the doctrine of separation of powers in its absolute rigidity but the functions of the different parts or branches of the Government have been sufficiently differentiated", so that it "does not contemplate assumption, by one organ or part of the State, of functions that essentially belong to another". In Kesavananda Bharati v. State of Kerala Sikri C.J. listed "Separation of powers between the Legislature, the executive and the judiciary" among the five features making up the basic structure, and Shelat and Grover JJ. held that the Constitution "creates a system of checks and balances by reason of which powers are so distributed that none of the three organs it sets up can become so pre-dominant as to disable the others". The doctrine here is therefore not enforceable as a free-standing rule, but it is enforceable against a constitutional amendment.

Where the Constitution does the demarcating

No article says "the three powers shall be separate". The separation is done by vesting, and a good answer points to the vesting articles rather than to a slogan.

• The executive power. Article 53(1): the executive power of the Union "shall be vested in the President and shall be exercised by him either directly or through officers subordinate to him". Article 154(1) says the same for a State and the Governor.
• The legislative power. Article 245(1): "Parliament may make laws for the whole or any part of the territory of India, and the Legislature of a State may make laws for the whole or any part of the State." Article 246 then divides the subjects by the three Lists, worked out in [The Legislative Lists].
• The judicial power. Articles 124 onwards constitute the Supreme Court and articles 214 onwards the High Courts, and articles 32 and 226 place enforcement of the Constitution in their hands.

That demarcation is real. What it is not is a wall, because the same Constitution deliberately joins two of the three organs.

The join, and the article that keeps one gap open

Article 74(1) requires a Council of Ministers "to aid and advise the President who shall, in the exercise of his functions, act in accordance with such advice", and article 75(3) makes that Council "collectively responsible to the House of the People". The real executive therefore sits in the legislature and survives only while it commands a majority there. That is the British arrangement, adopted on purpose.