At least 13 people have been killed in an explosion at a firecracker factory in India's southern state of Kerala, officials say. The incident took place in Thrissur, where around 40 people were believed to be assembling firecrackers in a cluster of sheds for an upcoming festival. Several others were injured, with five reported to be in critical condition.

This was the second such incident this week. On Sunday, a blast at a firecracker factory in neighbouring Tamil Nadu state left at least 25 dead. Accidental explosions are a grim routine in India's fireworks industry, recurring with troubling regularity - most visibly around Sivakasi in Tamil Nadu, which produces much of the country's supply.

The explosion in Thrissur on Tuesday sparked secondary blasts that hampered rescue efforts. Firecrackers were being made in temporary sheds near paddy fields with poor road access. The force of the blast was felt kilometres away, and nearby homes were damaged. Eyewitnesses reported chaotic scenes as locals joined rescue efforts to pull the injured and dead from the debris.

Kerala's Revenue Minister K Rajan assured that all fireworks units had the necessary permission to manufacture and store fireworks. The workers were preparing for the Thrissur Pooram festival, which involves famed fireworks displays.

A magisterial inquiry has been ordered to determine the cause of the blast. Kerala's Chief Minister Pinarayi Vijayan vowed to provide medical assistance from other states for burn victims if necessary. Prime Minister Narendra Modi announced financial support for the families of those affected.

This disaster underscores the urgent need for stringent safety regulations within an industry often marked by lax enforcement and high demand around festival times.