What was going on when I was born?

Sales by businesses plunged 2.1 percent in June, the second biggest decline on record, as unsold inventories continued to pile up and give further evidence of a weak economy. The Commerce Department said yesterday that sales at the retail, wholesale and manufacturing levels dropped to $419.1 billion in June after a four-tenths of 1 percent increase in May. The decline was the second largest monthly drop since the Government began keeping records on total sales in 1967. The biggest decline was a 2.8 percent fall in March 1975.

The White House staff has drafted an executive order repealing requirements that Federal contractors set numerical goals to remedy possible job discrimination. White House officials contend that the existing rules have not significantly helped blacks in low-wage jobs, have encouraged employers to discriminate against white men and have imposed costly compliance burdens upon employers. Since 1968 thousands of Government contractors have been required to hire and promote blacks, women and Hispanic people in rough proportion to the number of available, qualified candidates in a given labor market. Reagan Signature Required As drafted, the order would also forbid the Labor Department to use statistical evidence to measure contractors' compliance with general prohibitions against discrimination, which would remain in force. For years the department has routinely used statistical evidence to assess whether contractors were discriminating against women and members of minority groups.

A HOUSEWIFE unpacks a new set of dishes and fits them into the narrow cabinets of her galley kitchen. Across the hall, her neighbor, an architect, has spent the weekend building free standing closets in his apartment. He judges the height and width by eye and corrects the proportions as he goes along. Though entirely different tasks, both people are relying on their ability to perceive three dimensional objects and their spatial relationships, a skill that is almost second nature in activities such as driving a car, threading a needle or throwing a Frisbee. Spatial skills are also relied on in many professions including medicine, architecture, engineering, landscaping, dentistry and automobile maintenance.

International Morocco will soon finish building a wall of sand and electronic sensors that is greatly revolutionizing antiguerilla tactics, according to senior Moroccan military officers. The wall, which was started five years ago, will stretch for more than 1,560 miles across the Sahara. The wall is expected to help Rabat in its nine-year-old war against Polisario Front rebels. [Page A1, Columns 3-4.] South African violence claimed three more lives in townships. The incidents took place amid expectations that President P. W. Botha will make a major policy statement on apartheid. The three deaths brought the death toll in the last 11 months to at least 618. [A6:1-3.]

Of all the disputed military contract charges the General Dynamics Corporation has grappled with, perhaps the most politically embarrassing case involved a dog named Fursten. Fursten, a General Dynamics executive's dog that was lodged at a kennel at Government expense, became the comic symbol of a powerful offensive against overhead abuses in the weapons industry. The case led, in part, to five months of Defense Department penalties against General Dynamics. On Tuesday, however, the Navy announced that it had lifted its ban on new contracts to the company, saying General Dynamics had taken steps to rectify contracting abuses. And what is more, the Pentagon, which had heatedly denounced General Dynamics in May for ''pervasive'' business misconduct, now said that what the company had been doing was permitted by existing regulations.

New York City Business, the one-and-a-half-year-old publication that has chronicled the ups and downs of doing business in New York, has discovered first-hand how competitive a market the city can be. Employees at City Business were shocked to learn yesterday that their publication had been sold to Crain Communications Inc., which announced that it was closing it down. The new owner publishes Crain's New York Business, City Business's competitor in the field of local business journalism. The Chicago-based Crain, which also publishes Advertising Age, Automotive News, Electronic Media and local business publications in Chicago, Cleveland and Detroit, declined to disclose the terms of the transaction.

Within about 10 days, Morocco will finish building a huge wall of sand and electronic sensors that is revolutionizing antiguerrilla tactics, according to senior Moroccan military officers. The wall, begun five years ago, is helping Rabat in its nine-year war against Polisario Front rebels. When complete, it will stretch more than 1,550 miles across the Sahara from the Algerian and Mauritanian borders to the Atlantic ocean, the Moroccan officers say. Western diplomats said they were studying the Moroccans' use of American and French-supplied radar and sensors as well as Moroccan military tactics. One official called the war the most conspicuous success of the use of high technology against a guerrilla army equipped with sophisticated Soviet weapons.

Mayor Koch yesterday stepped up the campaign to conserve New York City's dwindling water supply, announcing new enforcement measures and ordering the installation of water-restricting shower fixtures in more than two million apartments, hotel rooms, hospital rooms and offices. With the city reservoir system nearing the half-empty point, the Mayor sharply increased fines for violations of drought emergency regulations and said police surveillance helicopters would be used to spot illegal lawn-waterers. Mr. Koch announced the new moves at a City Hall news conference on the hottest day of the summer, a day when the temperature reached 94 degrees and New Yorkers did whatever they could to stay cool. [Page B1.] 'Water Rats' Denounced The Mayor praised public-spirited citizens who report recalcitrant landlords and ''neighbors who sneak out at night to water the lawn.'' And, as some city workers in the audience hissed at the very term, Mr. Koch denounced violators as ''water rats.''

The images this weekend linger. Black South Africans tear down the former home of Mohandas K. Gandhi outside Durban systematically, seeing a shrine of peace as no more than a source of free building material. A day later, a black crowd incinerates a fellow black depicted as a sellout. There is to it all a harsh logic and a kind of explanation. But the beneficiaries include those who seek evidence of black violence with which to counter black political demands. The damage seems to go deeper than points scored in a propaganda battle. Within less than a week, in which bloodshed has spilled far beyond the areas affected by the state of emergency, blacks have shown themselves sharply divided.

A table in Business Day on Monday with an article about second-quarter sales and profits misstated Johnson & Johnson's earnings increase. It was 30 percent, over the 1984 quarter.

Bear, Stearns & Company, a Wall Street maverick that is one of the few remaining large brokerage partnerships, has decided to make its first public offering of stock and debt securities, Alan C. Greenberg, its chief executive, said yesterday. ''Our intention now, unless there are unforeseen circumstances, is to make the offering,'' Mr. Greenberg said in a telephone interview. The executive committee of Bear, Stearns - known as one of Wall Street's scrappiest, high-stakes traders - formally made its decision on Aug. 5, Mr. Greenberg said. It was reported in late July that the firm was considering options for raising capital.

The leak of a toxic chemical from a Union Carbide plant in Institute, W.Va., coming after a number of less serious but widely publicized accidents across the country, has sent an alarm through the chemical industry. Executives said today that they are bracing for greater Government regulation and more intense public scrutiny. The major chemical companies say that in the months since a gas leak killed hundreds of people at a Carbide plant in Bhopal, India, wide-ranging efforts have been undertaken to improve the safey of plants. But, after the Institute accident, and others this week near Charleston, W.Va.; Camden, N.J.; Valentine, Ariz., and Fairfax, Va., the executives said it will be a formidable task to calm public fears and placate Congressional critics.