Kishwar Desai calls her novels social thrillers; books set in the beating heart of modern-day India that lay bare its cauldron of inequalities, injustices and cultural traditions. The first, 2010's Witness the Night, won the Costa first novel award  and deservedly so; it somehow managed to deal with the hidden world of female infanticide in India without ever resorting to heavy-handed polemic.

That it worked so well was in no small part thanks to Desai's engaging social worker-cum-detective protagonist Simran Singh, who lightened the mood with her dismissive attitude towards her mother, health and authority in general. So it makes sense that she returns for the follow-up, Origins of Love  but this time she finds herself entangled in India's shockingly prevalent surrogacy industry.

In places, this is a tough  but hugely necessary  read. Desai expertly renders the clinics into which poor young Indian women are forced, by economic or family pressures. They are little more than battery farms for the hopeful western parents who courier embryos to Mumbai for the surrogates to carry for nine months. When the baby is delivered, the parents fly to the clinic and pick up the child. Job done.

Outsourcing a pregnancy to India might sound fanciful, but it is legal. Desai says 25,000 babies are born to surrogates there every year, and abuse and exploitation in the system is rife, because everyone is making money. To her immense credit, Desai not only shows both sides of the story  she's at pains to explain the imperative behind the decisions made by an English couple desperate for a baby  but fashions a page-turning narrative from the issue. An abandoned surrogate baby is born HIV-positive, her parents suspiciously die in an accident and Simran is immediately on the case, encountering a threat to her own life and happening across endemic corruption and illegal stem-cell research. The subplot in which two Brahmin politicians have their embryo carried by a Dalit surrogate in order to create a political dynasty that will appeal across the voting spectrum is wincingly possible.

And while the episodic nature of Origins of Love gives it the whiff of a soapy, serialised tale in a women's interest magazine, Desai's books are now bestsellers in India. Women politicians have begun to question the industry  suggesting that fiction can have the same power to change and provoke as, say, Siddhartha Deb's brilliant nonfiction book on India, The Beautiful and the Damned. In a month where Indians themselves have begun to question the very fabric of their society, Kishwar Desai's work would appear to be crucial.