The reduction of the anomalous transport due to the inhomogeneous radial electric field is theoretically studied for toroidal helical plasmas. The self-sustained interchange-mode turbulence is analysed for a system with magnetic shear and magnetic hill. The ballooning mode turbulence is studied for a system with magnetic well-like conventional stellarators. The influence of the radial electric field inhomogeneity on the transport coefficients and fluctuations is quantitatively shown. Unified theories of the transport coefficients in the L-mode- and H-mode-like plasmas are presented.