Solar stocks and related exchange traded funds have powered ahead and are among the leading sectors over the first quarter after underperforming the equities market last year.

The Guggenheim Solar ETF (NYSEArca: TAN) is the third best performing ETF for the first three months of the year. TAN has increased 31.6% year-to-date. [Solar ETFs: Industry Growth Not Reflected in Market]

Additionally, other clean energy ETFs were among the top ten performing non-leveraged ETFs so far this year, including the iShares Global Clean Energy ETF (NYSEArca: ICLN), which rose 22.8%, and the Market Vectors Solar Energy ETF (NYSEArca: KWT), which gained 22.6%. ICLN tracks a broader exposure to clean energy stocks, including solar, wind and other renewable resources.

Solar stocks have been steadily strengthening in response to the growing discussion over China’s severe pollution problem, which was recently highlighted in a 104-minute documentary video over the weekend titled “Under the Dome.”

Jefferies analysts argue that this could be a “watershed moment” for China’s environmental policy. Consequently, the firm believes investors should jump into green energy stocks and shun big oil and coal. [Solar ETF Provides a Ray of Sunshine]

Helping the solar industry shine brighter over the first quarter, China has been raising its solar capacity target in an attempt to rein in its pollution problems. For 2015, Beijing has promised to add almost two-and-a-half times as much capacity as the U.S. added last year, installing as much as 17.8 gigawatts of solar, Bloomberg reported.

“This will benefit equipment suppliers that focus on the domestic market,” Yin Lei, an analyst at China Merchants Securities Co., said in the article.