Production Details:
Though there is no clear production data available, but it is estimated that about 10% of total rice production is used for flaked rice, expanded rice and popped rice. Orissa, Maharashtra, Madhya Pradesh, Chhattisgarh are the major poha manufacturing centers of India.

The process of poha production is explained below:

The Pollution Problem:
Out of these, roasting is one of the very critical process of the entire production which adds ‘crispiness’ to the poha and the color. Nowadays, continuous-type cylindrical roasters are commonly used for roasting the paddy. During the roasting process, the sand is heated to 170-220 deg Celsius. This heat is either supplied by burning natural gas or locally available biomass fuels (such as saw dust, rice bran/husk etc.) in the highly inefficient combustion chambers. When such biomass fuels are used, it contributes greatly to the environmental pollution because of the high ash/moisture content of the fuel and inefficient furnaces.

As observed in the industries of Bhatapara (Chhattisgarh) and Ujjain (Madhya Pradesh), some of the common features of these roasters are:

• Convective heat loss due to lack of insulation: The furnaces of most of the roasters are designed with normal construction bricks and without any insulation.
• Radiative heat losses due to manual ash removal: These furnaces also have an ash removal opening which also work as an inspection hole. The plant operator uses this to manually remove the hot ash from the furnace. This opening doesn’t have any door to close which results in high amount of heat loss through radiations.
• High flue gas heat losses: The ash removal opening also let high amount of excess air to enter the furnace leading to high amount of heat being lost with flue gases. High excess air also leads to drop in the furnace temperature resulting in incomplete combustion of the fuel and often lead to black smoke coming from the chimneys.
• Wrong selection of fuel: The industry relies majorly on cheap, locally available biomass fuels such as rice bran, saw dust, wood etc. Though the cost per kilogram of these fuels are very low, but these fuels often have high moisture and ash content resulting in heat losses. Due to this, more quantity of the fuel is required to supply a given amount of heat. This often leads to high monthly fuel cost bills and pollution.
• Manual Operation: The ash removal opening also works as an inspection window. The plant operator inspects the color of the combustion chamber to judge the temperature of the chamber and then manually adjust the fuel feeding. The poor judgement can lead to excess or insufficient fuel supply, leading to change in the temperature of the furnace affecting the quality of the poha and the gaseous emissions as well.