The oil giant Shell is being accused of a new oil spill in southern Nigeria. The Nigerian NGO Environmental Rights Action says it has observed an “extensive” spill on the Brass River in the Niger Delta. Shell has shut down an oil processing site but denies claims of a large spill. The news comes days after Exxon Mobil acknowledged a separate oil spill in the Delta. A U.N. report one year ago said the region will already need 30 years and around $1 billion to at least partially recover from environmental damage caused by major oil companies over several decades.