The coronal mass ejections (CMEs) and solar flares are the most important eruptions to decide the geo-space weather. The fast and wide CMEs and solar flares associated shocks generate the type II radio bursts emission occurs at the local plasma frequency and/or its harmonic. Such CMEs are capable of producing adverse space weather because they accelerate energetic particles and can cause geomagnetic storms when it is Earth-directed. The solar flare associated CME kinetic energy essentially organizes the three ranges (wavelength domains) of type II radio burst: metric, DH, and km. The m-to-km type II radio bursts are associated with more energetic CMEs than type II radio burst observed only in the single wavelength domain. The formation of shocks at longer wavelength near the Sun is a good indicator of geomagnetic storms and SEP events. It has important implications for the space weather studies. Some important recent results will be discussed in this presentation.