I was not surprised by the resignation of Arvind Subramanian. I gave no credence to the unspecified "personal reasons" he gave in his public statement - everyone who leaves for embarrassing reasons calls them personal and leaves it to readers to guess. For four years, I had read Arvind's superb Economic Surveys - the last one got 9.5 million hits from 196,000 visitors from 163 countries in one month - and noted their complete disconnection with the budgets that followed them. I read the finance minister's speeches out of duty, and noticed how innocent they were not only of the enormous knowledge that went into the Economic Surveys, but of economics altogether; all that he did was hand out billions and billions to party favourites and supporters. He did not need the CEA's expertise to do this; and while the CEA defended the government's economic policies when he could, he never defended his ministry's patronage business. So I assumed that the finance minister and his CEA lived in different worlds, and went on separately to do what they wanted. And when Arvind resigned, I presumed that he had finally got tired of the ministerial cold shoulder and left for a more welcoming environment. Arvind could be seen in the background in the budget-day photos of the finance minister. He also used to barge in unannounced on the finance minister, though he is not known to have interrupted any siesta. But such unplanned interaction is not enough to convey economics to the finance minister. Arvind can find better listeners; the tweets he gets after his public lectures are proof enough.

But I was probably quite wrong. Arvind acquired a mass of knowledge about the Indian economy while he was CEA. He was an extremely popular and much invited speaker, and he clearly enjoyed the interactions with his audiences. From the limited feedback I have got, he was on good terms with his fellow bureaucrats; at any rate, he was not made to feel unwelcome. So my relief at his leaving an unappreciative minister and a ministry that had no use for him must be tempered; for him, it was time well spent and enjoyed.

Now I am concerned about all the knowledge he acquired. A lot of it is ensconced in his Economic Surveys; but I hope what is still in his mind will not be wasted. It would be best used if a future prime minister made him finance minister. That is unlikely to happen, since the present prime minister is likely to return next year in the company of his finance minister. The next best thing would be if Arvind wrote down his thoughts on the Indian economy and put them out in books or blogs. He covered an enormous range of subjects in the surveys. But there are some which are more important to India and on which his knowledge is ahead of the field. I would like to mention some of them.

The first one is one Arvind took up in his first - 2015-16 - survey: low investment ratio, stalled projects, debt overhang, and the twin balance sheet problem. He had public differences on it with Raghuram Rajan. The finance minister did not renew Rajan's term and, in effect, got rid of him and brought in Urjit Patel. He also brought in the new bankruptcy law. But legal process takes ages in India, so the problem is miles away from solution. Arvind had recommended that India should take quick, decisive action on non-performing assets; the government did exactly the opposite. He should apply his mind to it looking back on the errors of the last three years.

Arvind had made a rather weak case for India's position in international negotiations on climate change - that India used to subsidize petrol and diesel oil, and had stopped doing so and collected modest taxes on both. He hoped that development of technology would eventually lead India to rely more on solar power. Climate change is deadly serious; India has deliberately chosen to ignore it. When it comes to policy, taxes and subsidies are just one issue; far more important is designing a more energy-efficient economy. That is what Arvind should turn his attention to.

The prime minister had come up early on with the slogan of Make in India; Arvind took a diplomatic or perfunctory look at it as the case may be. The question is, what to make in India? The implicit idea in Make in India, namely manufacture in India, makes no economic sense: India should make what it can make cheaply, and import what it makes at high cost. India has crores of unskilled workers, whom it should use. But if the prime minister is to be obeyed, it would be best to educate workers and give them skills that can be used to make something. Arvind outlined how laws and regulations had restricted employment in big firms, but employers had found ways, legal and illegal, around the regulations, which satisfied him; he did not advocate legal reforms.

Arvind uncovered enormous subsidies the government gives to the rich on air and rail travel, petrol and diesel, and gold; these should be revoked or, if that is not possible, countervailed.

Every state in India was a separate market for electricity. The division of the market led to small, expensive power plants. Each state set its own pricing policies which hugely subsidized farmers and exploited industrial consumers. The latter were allowed to produce power for themselves, but their costs too were high because of small scale. The result was an extremely inefficient power system which made it difficult for industry to be competitive internationally. Arvind did not spell it out, but the industry calls for a single national market, subsidies to consumers and not to producers, and unrestricted competition.

Arvind showed how, as India got richer, the preference for sons (and the consequent female infanticide and foeticide) increased. Just as India is working to improve its ease of doing business, it should work to improve its sex ratio.

He collected and analysed statistics relating to the judicial system, and came up with recommendations on accelerating and improving the judicial process. Even the judiciary has been struggling with this problem; it would find it useful to start from the ninth chapter of the last Economic Survey.

This is a very brief summary of the important matters to which Arvind applied his analytical talents. There is much more to his Economic Surveys. Even if he proceeds to advise more receptive governments and analyse more difficult problems elsewhere, Indian policymakers will find a treasure of ideas in his surveys that they can go on mining for some years. The only problem to which he did not apply his mind was, how can the Indian democratic system be reformed so that we get rulers who would look for, understand, use and implement bright ideas like Arvind's? His omission is perhaps understandable; it is inconceivable that our present rulers would pass on India to a more competent set, let alone redesign the electoral system to throw out the corrupt and the incompetent and bring in the likes of Arvind Subramanian.