A 48-year-old nonsmoker man, cotton mill worker, working in the carding department for 27 years, presented with progressively worsening dyspnea on exertion and dry cough for a period of 2 years. He did not give history of work-related exacerbation of symptoms. There were no significant systemic complaints. The baseline and postexercise saturation was 98% and 93%, respectively. Bilateral fine end inspiratory crackles were noted on respiratory system examination. Hematological, biochemical, and sputum examination did not show any significant abnormality. Chest radiograph showed scattered nodular opacities. The high-resolution computed tomography (HRCT) of thorax is shown in Figure 1. The spirometry was suggestive of mild restrictive abnormality with forced vital capacity (FVC) of 3.06 (72% predicted), forced expiratory volume in one second (FEV1) of 2.57 (74% predicted), and FEV1/FVC 84%. The transbronchial lung biopsy showed focal scarring with heavy deposits of anthracotic pigments; patchy peribronchial, alveolar septal thickening, and smooth muscle proliferation [Figure 2].