"Are becoming"? The only thing new in the last decade is that foreign manufacturers are jumping into the market, and that more people now have the means and avenues for upward mobility, and increased use of skin-lightening products is part of a general increase in consumption on the path to the middle class (including cars etc.). With the increased money, the manufacturers can now hire bigger celebrities to advertise the products (like Shah Rukh Khan, bless his innocent little heart; he appears to have no idea in the ads he acts in, that he might be participating in something potentially problematic).

In other words, the latent demand was always there. And until very recently, there has never been any racial uneasiness about it, or even any thought that it might be a problematic attitude. Indians generally see no difference between complimenting someone "wow, you are tall" or "your eyes are beautiful" and "hey, you are looking fairer." It is a completely unreconstructed light-skin preference.

But those who want to problematize and deconstruct light-skin preference in India are taking on far more than they know. The issue is way more murky than people realize.

Such products have been popular for centuries, and pre-date European influence. The brands and manufacturers have changed that's all. There are plenty of home remedies (based on turmeric for example) that are claimed to have skin-lightening properties. I recall reading an account of a visit to India by a 17th century European (it was possibly the account of Tavernier, the French jeweler who bought the Hope diamond, but I am not sure) where he notes something along the lines of "the people of hindoostan, like us, prize fair-skinned women."

Don't hold me to the correctness of the reference, this is from long-ago reading. But I am willing to bet they had skin lightening in the Indus valley civilization, 3400-1900 BC (they've found evidence of a lot of other kinds of cosmetics I believe). The only curious phenomenon is that there has always been a very minor, but historically continuous positive connotation to dark skin as well, starting with the (dark-skinned) Krishna of the Mahabharata. But AFAIK, this has been restricted to males.

And not just India. The entire stretch from the Middle East to the easternmost parts of Indonesia. Skin lightening products are popular.

In a lot of other countries, such as Japan, skin lightening products might not be used (I don't know), but lighter skin is nevertheless overtly preferred. And as the quote shows, within the European spectrum too, lighter skin has historically been preferred (though it is less noticeable due to the overall lighter spectrum). "Fair" is a synonym for "beautiful" in English just as "gori" is a synonym for "pretty woman" in Hindi.

So I'd guess it is pretty much global actually. The only region I'd exclude is sub-saharan Africa proper. I suspect you might find true cultural dark-skin preferences there. In black America (so black friends have told me), the lightening-product phase vanished in the 30s, but the debate didn't go away. It just went underground, and there's something of an aesthetics divide between the more European-looking vs. African looking parts of the community.

Those who are suggesting that tanning is in some way a symmetric dual of a light-skin preference are being a little disingenuous. Tanning is a far simpler and more superficial cultural phenomenon, that has more to do with wanting to look sportsy/outdoorsy than a deeply-rooted part of social identity. It cannot be considered a hypothetical dark-skin preference.

Is it troubling? It used to trouble me when I thought I understood the issue. Now I know I don't understand it. Race, culture, history, homophily, impact of media, genetics, the unrelated connotations of good/evil day/night knowledge/ignorance (via the light/darkness metaphor)... all sorts of things are mixed up in causing the phenomenon.

But curiously, the more I understood how little I understood, the less the issue bothered me.

There's certainly a couple of anthropology PhDs waiting to be earned here though.