was it ever ruled by someone?
Yes. Portuguese and British
Mumbai
 On 11 May 1661, the marriage treaty of Charles II of England and Catherine of Braganza, daughter of King John IV of Portugal, placed the islands in possession of the English Empire, as part of Catherine's dowry to Charles. 
why mumbai is called financial capital of india It generates 6.16% of the total GDP what can you tell about the people of this place? A resident of Mumbai is called "Mumbaikar" in Marathi, in which the suffix "kar" means a "resident of"
wiki:25593957
Mumbai [SEP] Portuguese and British rule
By the middle of the 17th century the growing power of the Dutch Empire forced the English to acquire a station in western India. On 11 May 1661, the marriage treaty of Charles II of England and Catherine of Braganza, daughter of King John IV of Portugal, placed the islands in possession of the English Empire, as part of Catherine's dowry to Charles. However, Salsette, Bassein, Mazagaon, Parel, Worli, Sion, Dharavi, and Wadala still remained under Portuguese possession. From 1665 to 1666, the English managed to acquire Mahim, Sion, Dharavi, and Wadala. In accordance with the Royal Charter of 27 March 1668, England leased these islands to the English East India Company in 1668 for a sum of £10 per annum.