We present evidence for anomalous microwave emission in the RCW175 H ii region .
Motivated by 33 GHz 13 \arcmin resolution data from the Very Small Array ( VSA ) , we observed RCW175 at 31 GHz with the Cosmic Background Imager ( CBI ) at a resolution of 4 \arcmin .
The region consists of two distinct components , G29.0-0.6 and G29.1-0.7 , which are detected at high signal-to-noise ratio .
The integrated flux density is 5.97 \pm 0.30 Jy at 31 GHz , in good agreement with the VSA .
The 31 GHz flux density is 3.28 \pm 0.38 Jy ( 8.6 \sigma ) above the expected value from optically thin free-free emission based on lower frequency radio data and thermal dust constrained by IRAS and WMAP data .
Conventional emission mechanisms such as optically thick emission from ultracompact H ii regions can not easily account for this excess .
We interpret the excess as evidence for electric dipole emission from small spinning dust grains , which does provide an adequate fit to the data .