This investigation aims to identify the reasons for the plumes' visibility, compare the stacks with other sinter plant stacks worldwide, and suggest countermeasures to completely stop the visibility of emissions. The appearance of the sinter plant stack emission changes with time and the background color of the sky due to the scattering effect of the sunlight and incidence angle. The flue gas samples were collected at the outlet of the emission control equipment and observed under optical and scanning electron microscopes. The characterization was performed with the help of an electron dispersive spectroscope and mapping technique. The contents of the stack of a sinter plant without a bag filter had much higher levels of PM 10 , SO 2, and NO x . The emissions from all the sinter plants were invariably found to have particulates of SO 2 and NO x of size less than 2.5 microns. It is suggested to opt for state-of-the-art fabric filter technology to eliminate PM 2.5 emissions also. Graphical Abstract