The Ministry of Agriculture and Farmers Welfare, through the Department of Agriculture and Farmers Welfare, has notified the mandatory specifications for Phospho Gypsum to be manufactured in India. These specifications are issued in pursuance of Clause 20A of the Fertiliser (Inorganic, Organic or Mixed) Control Order, 1985. The standards are applicable for a period of 3 years from the date of publication of the notification on 3 December 2025.
The mandated specifications for Phospho Gypsum are as follows:
| Parameter | Specification |
| Moisture per cent. by weight | Maximum 15.0 4 |
| Sodium content (as Na) per cent. by weight (on dry basis) | Maximum 0.75 5 |
| Sulphur (as S) per cent. by weight | Minimum 13.0 6 |
| Calcium Sulphate dihydrate content per cent. by weight (on dry basis) | Minimum 70.0 7 |
| Fluoride (as F) per cent. by weight | Maximum 1.0 8 |
| Particle Size | The material shall pass through a 2 mm IS sieve and 50 per cent. of it shall pass through a 0.25 mm IS Sieve (60 mesh) 9 |
Heavy Metal Content
The maximum limits for heavy metals in Phospho Gypsum are also specified:
| Heavy Metal | Maximum Content (as mg per kg) |
| Lead (as Pb) | 100.0 10 |
| Cadmium (as Cd) | 5.0 11 |
| Chromium (as Cr) | 50.0 12 |
| Nickel (as Ni) | 50.0 13 |
| Arsenic (as As2O3) | 10.0 14 |
| Mercury (as Hg) | 0.15 15 |