light scattering propeties of interstellar and circumstellar dust provide an important diagnostic tool for study of the size
composition of this kind of dust and help in explaining the observational characteristics like extinction , emission features , polarization etc. the talk will describe effective medium approximation; T-Matrix and discrete dipole approximation based models for the light scattering study of such dust and obtain satisfactory explanation for the observed IR emission features in circumstellar dust i.e.,