<prompt> As per the World Health Organisation guidelines, iodine deficiency disorders are endemic in a community if the prevalence of goiter in school age children in more than -151015  <response>: Epidemiological criteria for assessing severity of IDD. Total goitre Rate TGR : Grade I Grade II Median urinary iodine excretion. Thyroid volume Ultrasound. Salt iodine content Criteria for sustainable elimination of IDD. Median Urinary Iodine Excretion 100 mcgL Level of iodization: 1 30ppm at production level 2 15 ppm at consumer level Total goitre Rate TGR :5 Ref: Assessment of IDD and monitoring their elimination, WHO 3rd edition 