Nigeria's Dangote refinery, built at a cost of $20 billion and is Africa's largest, has started exporting naphtha to North Asian markets at a time when the clean tanker market is witnessing prolonged firmness. The naphtha flow from Dangote is adding to the ton-mile demand in the clean tanker sector and this could be boosting the clean tanker market in the short- to medium term.   Associate editorial director for Asia Freight, Pradeep Rajan, discusses about West African naphtha flow and its impact on the clean tanker market with Sameer Mohindru, senior editor, Asia clean tanker market, and associate editor Zoey Ng, who covers Asia naphtha market.