Mohamed, 80, collapsed on the ground. He says: 'I'm here because I'm hungry. I cannot walk. My legs are swollen. I travelled by camel to get here. I have been here for two months. This is the worst drought I remember since I was born. There is no rain. All my livestock is dead. My hand has become like this because of hunger. I used to drink milk, but all my camels are dead. I had 50. They are all dead. They died in 2015. Yesterday I tried to eat rice but I couldn't swallow. I drink black tea. It is five months since I had proper food. We need help.' A devastating drought is causing the worst food crisis to hit Ethiopia in 30 years, putting millions of people at risk of hunger and disease.