Well that was fast. Only a short 15 months after New Delhi announced its plan to open up the big-box retail industry to foreign investment, leaders have finally found their first taker. Britain’s Tesco  last month unveiled a $110 million plan for a joint venture with the supermarket subsidiary of Tata to operate a string of supermarkets. And with atypical alacrity, regulators on Monday approved the deal barely two weeks after it was submitted to their consideration. A sign that India is finally (re)opened for business?

Not precisely. Instead, recent developments in the country’s retail industry provide yet another in a long list of teachable moments for both Indian politicians and voters. One can only hope the lessons sink in before elections due in May.

The TescoTSCO.LN -0.01% story confirms a warning highlighted in this column in September 2012. At that time, you’ll recall, New Delhi had finally, after years of wrangling and waiting, unveiled a plan to loosen investment rules for foreign retailers. Previously, single-brand retail (such as Nike stores or Prada boutiques) had been restricted to 51% foreign ownership. Foreign investment in multi-brand retail—big-box stores such as Wal-MartWMT -0.05%, Tesco or Carrefour that carry a range of products—was prohibited. The reform proposal allowed 100% foreign ownership of single-brand outlets and 51% foreign ownership of multi-brand stores in cities of a certain size, subject to local approval and various other conditions.

This was hailed as a breakthrough, given that investors had clamored for such measures for so long and Prime Minister Manmohan Singh‘s failure to liberalize retail had come to represent his broader shortcomings as a reformer. But in key respects the breakthrough came too late.