More specifically, bubbles in emerging markets — short answer, no.
From the link, a bit more behind the short answer:
So what does all this mean for investors? ETFs probably haven’t caused a bubble, and they might even help a bit to prevent one from forming. But many will remain superconcentrated bets on very risky markets. If you invest in an ETF with most of its assets in a few stocks and think you have made a diversified bet, the real bubble is the one between your own ears.